Forensic science books for beginners

Forensic science books for beginners DEFAULT

Forensic Science

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Siegel

Mirakovits

FORENSIC SCIENCE

the basics

Second
Edition

Second Edition

FORENSIC
SCIENCE
the basics

About the Cover
Growing rusticles (3, RST) became important after researches of the wreck site of the RMS Titanic
off the continental shelf in the North Atlantic. The exposed steel surfaces of ship appeared to be
coated with rusticles. In and , expeditions recovered rusticles from the ship and by late
methods were found to culture these consormial growths in a laboratory. The picture shows the
manner in which rusticle growth may be enhanced using electrically impressed steel plates. In ,
the technology advanced to the point where an aquarium of cultured rusticles went on tour with the
Titanic Science exhibition organized by the Maryland Science Center. Over the next five years, more
than million exhibition visitors witnessed the growing rusticle consorms that formed in seven
distinct growth patterns.

Second Edition

FORENSIC
SCIENCE
the basics

Jay A. Siegel • Kathy Mirakovits

Boca Raton London New York

CRC Press is an imprint of the
Taylor & Francis Group, an informa business

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Dedication
To my family, Maggie, Paul, and Sam. They are my reason for being. Can
any legacy be as important? Thank you all for your love and support.
Jay Siegel
I dedicate this book to my father, Carl J. Busch, who always had
faith in my accomplishments. He quietly supported and gently
nudged me to push myself to the upper limits of my abilities.
Thank you, Dad. I hope you are smiling and applauding in Heaven.
Kathy Mirakovits

Contents
Foreword xv
Prefacexvii
About the Authors xix

Part I: Forensic Science and Investigation
Chapter 1: Introduction to Forensic Science
Learning Objectives
Mini Glossary
Acronyms
Introduction
What Is Forensic Science?
History and Development of Forensic Science
What Is a Forensic Scientist?
Career Information
The United States Forensic Science System
Other Forensic Science Systems
The Organization of Forensic Science Laboratories
Summary
Test Yourself
Further Reading
On the Web

Chapter 2: Crime Scene Investigation
Learning Objectives
Mini Glossary
Introduction
The Crime Scene as Recent History
Crime Scene Investigation Process
Summary
Test Yourself
Mini Lab Activities
Further Reading
On the Web

Chapter 3: The Nature of Evidence
Learning Objectives
Mini Glossary
Introduction
Classification of Evidence
Identification
The DNA Typing Situation
Positive and Negative Controls
Summary
Test Yourself
Further Reading

vii

viii Contents

Part II: Tools of the Trade
Chapter 4: Separating Complex Mixtures
Learning Objectives
Mini Glossary
Acronyms
Introduction
Physical Separation of Solid Mixtures
Solid Phase Extractions
Chromatography
Summary
Test Yourself
Further Reading
On the Web

Chapter 5: Light and Matter
Learning Objectives
Mini Glossary
Introduction
What Is Light?
Light as a Wave: The Electromagnetic Spectrum
Properties of Waves
The Energy of Light: The Photon
Interactions of Light Energy and Matter
Mass Spectrometry
Summary
Test Yourself
Further Reading
On the Web

Chapter 6: Microscopy
Learning Objectives
Mini Glossary
Acronyms
Introduction
Types of Microscopes
Forensic Microscopy
The Lens: How Objects Are Magnified
The Compound Microscope
Modifications of the Compound Microscope
Electron Microscopy
Summary
Test Yourself
Further Reading
On the Web

Part III: Patterns and Impressions
Chapter 7: Fingerprints and Other Impressions
Learning Objectives
Mini Glossary
National Institute for Standards and Technology (NIST) and
the National Crime Information Center (NCIC)
Introduction
The Quest for a Reliable Method of Personal Identification
The Origin of Fingerprints
The Anatomy of Fingerprints
Detection and Visualization of Fingerprints

Contents ix
Comparison of Fingerprints
Comparison of Single Fingerprints
Automated Fingerprint Identification Systems (AFIS and IAFIS)
Common Questions about Fingerprints
Other Impressions: Footwear and Tire Treads
Summary
Mini Lab Activities
Test Yourself
Further Reading
On the Web

Chapter 8: Questioned Documents
Learning Objectives
Mini Glossary
Acronyms
Introduction
What Is a Questioned Document?
The Questioned Document Examiner
Handwriting Analysis
Fraud and Forgery
Erasures, Obliterations, and Alterations
Typewriters, Photocopiers, and Computer Printers
Paper Examination
Ink Examinations
Physical Matches on Torn Paper
Summary
Test Yourself
Further Reading
On the Web

Chapter 9: Firearms and Toolmarks
Learning Objectives
Mini Glossary
Introduction
Firearms Identification
The Anatomy of a Live Round (Cartridge)
Examination of Firearms Evidence
Digital Imaging Systems for Ammunition
Distance-of-Fire Determinations
Toolmarks
Summary
Mini Lab Activities
Test Yourself
Further Readings
On the Web

Part IV: Forensic Biology
Chapter Forensic Pathology
Learning Objectives
Mini Glossary
Acronyms
Introduction
How to Become a Forensic Pathologist
Investigation of Death: Coroners and Medical Examiners
Death Investigation Process
The Postmortem Interval (PMI)—Time of Death
Embalming and Exhumations
The Teamwork Approach

x Contents
Summary
Test Yourself
Further Reading
On the Web

Chapter Anthropology and Odontology
Learning Objectives
Mini Glossary
Introduction
The Human Skeleton
Identification of Skeletal Remains
The Significance of Age
The Biological Profile
Individualization of Human Bone
Collection of Bones
Forensic Odontology
Summary
Mini Lab Activities
Test Yourself
Further Reading
On the Web

Chapter Forensic Entomology
Learning Objectives
Mini Glossary
Introduction
Becoming a Forensic Entomologist
The PMI: The Life Cycle of the Blowfly
Decomposition of a Body after Death
Factors That Affect PMI
Entomological Investigation and Evidence Collection
Summary
Test Yourself
Further Reading
On the Web

Chapter Serology
Learning Objectives
Mini Glossary
Introduction
Blood
Analysis of Blood
Other Biological Fluids and Stains
Bloodstain Pattern Analysis
Bloodstain Pattern Categories
Summary
Appendix A
Mini Lab Activities
Test Yourself
Further Reading
On the Web

Chapter DNA Typing
Learning Objectives
Mini Glossary
Acronyms
Introduction
What Is DNA?
Collection and Preservation of DNA Evidence
DNA Typing

Contents xi
The Polymerase Chain Reaction
Short Tandem Repeats (STRs)
Mitochondrial DNA
CODIS: The Combined DNA Index System
Summary
Test Yourself
Further Reading
On the Web

Chapter Hair
Learning Objectives
Mini Glossary
Introduction
What Is Hair?
Hair Growth
Hair Color
The Structure of Human Hair
Human versus Nonhuman Hairs
Hair Treatment and Damage
Comparison of Human Hairs
What Can Be Determined from the Structure of Hair?
DNA Analysis of Hair
Hair as a Source of Drugs
Summary
Test Yourself
Further Reading
On the Web

Part V: Forensic Chemistry
Chapter Illicit Drugs
Learning Objectives
Mini Glossary
Acronyms
Introduction
Illicit Drugs
The Control of Illicit Drugs in the United States
Classification of Illicit Drugs
Analysis of Illicit Drugs
Summary
Test Yourself
Further Reading
On the Web

Chapter Forensic Toxicology
Learning Objectives
Mini Glossary
Acronyms
Introduction
Forensic Toxicology
Principles of Pharmacology
Pharmacology and Toxicology of Ethyl Alcohol
Drunk Driving Laws
Field Sobriety Testing
Measurement of BAC
Summary
Test Yourself
Further Reading
On the Web

xii Contents

Chapter Fibers, Paints, and Other Polymers
Learning Objectives
Mini Glossary
Introduction
What Is a Polymer?
Textile Fibers
Types of Fibers
Fiber Morphology
Analysis of Synthetic Fibers
Chemical Analysis of Fibers
Interpretation of Fiber Evidence
Paints and Other Coatings
Types of Paint
How Cars Are Painted
Collection of Paint Evidence
Analysis of Paint
The Evidentiary Value of Paint
Summary
Mini Lab Activities
Test Yourself
Further Readings
On the Web

Chapter Glass and Soil
Learning Objectives
Mini Glossary
Introduction
Glass
Glass as Forensic Evidence
Analyzing Broken Glass
Soil
Summary
Mini Lab Activities
Test Yourself
Further Reading
On the Web

Chapter Fires and Explosions
Learning Objectives
Mini Glossary
Acronyms
Introduction
What Is a Fire?
Extinguishing a Fire
Incendiary Fires
Investigation of a Fire
The Role of Accelerants
Analysis of Fire Scene Evidence
Analysis of Accelerants
Explosions
Investigation of Bombing Scenes
Summary
Test Yourself
Further Reading
On the Web

Contents xiii

Part VI: Legal Aspects of Forensic Science
Chapter Forensic Science and the Law
Learning Objectives
Mini Glossary
Introduction
Admissibility of Evidence
Laboratory Reports
Expert Testimony
Summary
Test Yourself
Further Reading
On the Web

Foreword
If you were to ask middle school or high school teachers why they teach science,
their answers might not display a specific love for a particular area of science such
as physics or biology. The true love of teaching science stems from a thirst for problem solving and answering the questions of why and how.
When I first began teaching high school students nineteen years ago, I had a
predescribed checklist of science knowledge that I thought students had to master
in order to succeed in life. Within my first four months of teaching, I realized those
factoids didn’t matter to most kids. What became most important was the student’s
attitude toward science. Once students walked through my classroom doors as ninth
graders they had already formed their views of science as either boring, fun, or something for boys to do. My goal for my students was to foster a love for problem solving,
giving them a foundation of steps to begin to answer the why and how questions with
confidence and perhaps a little enthusiasm. I knew I was on the right track when on
the last day of school, one of my female students turned to me and said, “Thanks for
a great year. For the first time in my life, I actually enjoyed science!”
Traversing through my career of teaching earth science, integrated science, agriculture biology, animal physiology, veterinary science, and now biotechnology, I have
solidified my resolve that teaching high school students skills provides them the
foundation they need to academically succeed in any content area. Forensic science
naturally teaches students skills in observation, documentation, inquiry, literacy,
communication, and investigation, all while connecting academics to the working
world. Through the television experience of CSI, students make direct connections
to careers through forensic science. Even though glamorized, they see a range of
personalities performing as skilled lab technicians, crime scene investigators, medical examiners, and all areas of law enforcement. They see curiosity in action and
the range of skills and aptitudes required to perform the specific duties of the job.
Forensic Science: The Basics provides a much-needed resource for teachers and students. Each chapter is clearly mapped out with learning objectives and contains a
wealth of current content information, examples and illustrations, a useful summary, self-evaluation at the end of each chapter, and additional resources for further
comprehension. This book is critical for providing the content background necessary
for students to understand before they complete any laboratory experience.
Forensic science is exciting to teach and learn, as it is the realistic application
of all areas of science. Jay Siegel and Kathy Mirakovits have created a reliable and
fundamental resource to add credibility to real world science in the classroom. I
have worked with Kathy as a participant in her forensic workshops for teachers
and enjoy her passion for science and applaud the professional commitment she has
made to provide teachers with critical content and hands on training. I met Jay as a
guest presenter at one of Kathy’s workshops. I appreciate his understanding of the
need to provide a user-friendly resource connecting the bridge between college level
academia and middle and high school education.
Lori Steward
Linden High School science teacher
Linden, California

xv

Preface
Forensic science has changed quite a lot since the first edition of Forensic Science:
The Basics, was published in early Media coverage of the successes and failures of the criminal justice system and forensic science continues to increase as
does public interest in science and the law. The Innocence Project has helped free
more than wrongly convicted people to date. The validity of some traditional
forensic sciences such as fingerprints and firearms is being questioned by scientists,
judges, and lawyers. The number of high school classes in forensic science as well
as college degrees, both undergraduate and graduate, continues to increase. Case
backlogs nationwide have risen to more than , and there is a shortage of
qualified forensic scientists that is approaching 2, With all of these happenings,
there continues to be a need for quality forensic science text and lab materials that
provide students in high school and college with a solid education in forensic science
that builds upon a firm foundation in the sciences. Forensic Science: The Basics,
Second Edition, builds on the standard it set for introductory forensic science text
books and goes it one better.
Forensic Science: The Basics keeps the basic structure of the book, taking students through the criminal justice and forensic science systems from crime scene
to court. It builds a solid foundation of tools such as microscopy, spectroscopy, and
separation sciences and then applies them to the analysis of both the familiar types
of evidence such as DNA, drugs, and trace evidence, but still covers the not so commonly studied “-ologies”—pathology, anthropology, odontology, and entomology. The
book is flexible and comprehensive enough to be used in a one- or two-semester
class, giving the teacher maximum flexibility in topics to cover.
Even though the basic structure and chapters have stayed the same, there have
been big changes in the second edition. First, there are now two authors. In addition to Dr. Jay Siegel, a forensic scientist and college educator for more than thirty
years, Kathy Mirakovits has joined the team. She is one of the most experienced
and dynamic secondary school teachers of forensic science in the United States. She
not only teaches basic and advanced forensic science classes in Portage, Michigan,
she also conducts workshops for teachers all over the country and at national and
statewide science teachers’ meetings. She is also a consultant for a leading producer
of forensic science education kits and has developed many of her own materials. She
brings to The Basics the secondary school perspective that makes it even more relevant and appropriate for high school, community college, and university courses.
She has also taken the best from her workshops and incorporated them into Forensic
Science: The Basics. Each adopter will get a collection of laboratory exercises from
the basic to the advanced, with detailed instructions as well as lists and sources
of the materials needed. Other new features of The Basics include presentations of
real cases that illustrate the various types of forensic evidence, a mini glossary at
the beginning of each chapter, Web resources, mini lab exercises in most chapters,
up-to-the-minute information about forensic science, many new figures and photos,
and expanded questions at the end of each chapter. We are also planning a teacher’s
edition of the book and access to informative Web resources of Taylor & Francis.
We believe that Forensic Science: The Basics will meet and exceed your needs and
expectations for text material in your introductory or advanced class in forensic sciences. Feel free to contact us with your questions and comments.
xvii

About the Authors
Jay Siegel is currently director of the forensic and investigative sciences program
at Indiana University–Purdue University, Indianapolis, and chair of the department
of chemistry and chemical biology. He holds a Ph.D. in analytical chemistry from
George Washington University. He worked for three years at the Virginia Bureau
of Forensic Sciences, analyzing drugs, fire residues, and trace evidence. From
to , he was a professor of forensic chemistry and director of the forensic science program at Michigan State University in the School of Criminal Justice. Dr.
Siegel has testified as an expert witness more than two hundred times in twelve
states, federal court, and military court. He is editor-in-chief of the Encyclopedia of
Forensic Sciences, author of Forensic Science: A Beginner’s Guide and Fundamentals
of Forensic Science, and has had articles and papers published in more than thirty
forensic science journals. In February , he was named Distinguished Fellow
by the American Academy of Forensic Sciences. In April , he was named the
Distinguished Alumni Scholar by his alma mater, George Washington University.
Kathy Mirakovits teaches forensic science and physics at Portage Northern High
School in Portage, Michigan. She holds a master’s degree in science education from
Western Michigan University and a bachelor’s degree in science education from
Miami University. Kathy has also served as science department chairperson for six
years at Portage Northern. She taught at the high school level in Ohio, California,
and Michigan for almost twenty years, and during that time taught general science, physical science, chemistry, biology, Earth science, and physics. Additionally,
Kathy conducts workshops across the United States for teachers who wish to learn
the application of forensic science in a school curriculum. She has developed numerous forensic science educational products for a national science supplier and has
led workshops at the National Science Teachers Association (NSTA) in forensic science. Kathy led the teacher steering committee for the Forensic Science Educational
Conference sponsored by the American Academy of Forensic Science at Michigan
State University in August
Kathy has served as president of the Michigan Chapter of the American
Association of Physics Teachers (AAPT) and as a curriculum writer for the Michigan
Department of Education. Currently, Kathy serves as director-at-large for the
Michigan Science Teachers Association. She has received the RadioShack Science
Teaching Award and was a state finalist for the Presidential Award for Excellence
in Math and Science Teaching (PAEMST).

xix

P a r t

I

Forensic Science and Investigation

1

Introduction to Forensic Science

Learning Objectives
1. To be able to define forensic science and describe its various areas
2. To be able to describe the major events in the history of forensic science and relate them to
modern-day practice
3. To be able to describe the duties of a forensic scientist
4. To be able to describe the organization of federal, state, and local forensic science
laboratories
5. To be able to diagram and describe the flow of evidence through a crime laboratory
6. To be able to describe the qualifications for becoming a forensic scientist
7. To be able to obtain information on careers in forensic science

3

4

Forensic Science: The Basics, Second Edition

Chapter 1

Introduction to Forensic Science
Chapter Outline
Mini Glossary
Acronyms
Introduction
What Is Forensic Science?
Depth and Breadth of Forensic Science
Forensic Science v. Crime Scene Investigation
Criminalistics
Pathology
Anthropology
Odontology
Engineering
Entomology
Behavioral Forensic Science
Computer Forensics
History and Development of Forensic Science
What Is a Forensic Scientist?
So You Want to Be a Forensic Scientist
Career Information
The United States Forensic Science System
Federal Forensic Science Laboratories
The Justice Department
The Department of the Treasury
The Department of the Interior
The United States Postal Service
State and Local Forensic Science Systems
Private Forensic Science Laboratories
Other Forensic Science Systems
The United Kingdom
Australia
Colombia
The Organization of Forensic Science Laboratories
Summary
Test Yourself
Further Reading
On the Web

Mini Glossary
Behavioral forensic sciences: Applications of psychology and psychiatry to
criminal matters including competency, interrogation, and crime scene
reconstruction.
Computer forensics: Applications of computer science to criminal and civil
offenses including the use of computers to commit crimes and the use of computers to help solve crimes.

Introduction to Forensic Science 5

Criminalistics: Analysis of physical evidence generated by a crime scene. Also,
the pattern science areas of forensic evidence including fingerprints, firearms and questioned documents.
Forensic anthropology: Analysis of skeletal remains recovered from crime
scenes for the purposes of developing a biological profile and identification of
the remains.
Forensic engineering: Application of engineering principles in forensic cases
including failure analysis and traffic accident reconstruction.
Forensic entomology:  Study of insect activity and cadavers assist in the determination of time of death (postmortem interval) and for other forensic
purposes.
Forensic odontology:  Synonymous with forensic dentistry. Analysis of dentition
for the purposes of human identification and examination of injuries. Also
analysis of bite marks.
Forensic pathology:  Determination of the cause and manner of death in cases of
unattended or suspicious death.
Forensic science:  Application of science to matters involving the public or applications of science to legal matters.
Forensic scientist: A scientist who analyzes evidence generated by criminal or
civil offenses and who can offer expert testimony concerning the evidence in
court of law.
Lay witness:  A witness to a crime who testifies what she saw or heard. Lay witnesses do not normally give opinions. They are contrasted with expert witnesses who do have to render opinions at times.

Acronyms
AAFS:  American Academy of Forensic Sciences
BATF:  Bureau of Alcohol, Tobacco, and Firearms
CSI:  Crime scene investigation or investigator
DEA:  Drug Enforcement Administration
FBI:  Federal Bureau of Investigation
FEPAC:  Forensic Science Education Program Accreditation Commission
FSRTC:  Forensic Science Research and Training Center
FSS:  Forensic Science Service (United Kingdom)
FWS:  U.S. Fish and Wildlife Service
IRS:  Internal Revenue Service
LIMS:  Laboratory Information System
PCR:  Polymerase Chain Reaction
TSA:  Transportation Security Administration
USSS:  United States Secret Service

Introduction
Forensic science, forensic computing, forensic art, forensic accounting, forensic psychology. “Forensic” is the buzzword of the twenty-first century. It seems like there is
“forensic” everything. More than colleges and universities in the United States

6

Forensic Science: The Basics, Second Edition

and more than in the United Kingdom now offer some type of forensic science degree program. Movies, books, and TV shows about forensic science abound.
Everyone is familiar with the sight of a white-robed scientist peering into a microscope, staring at a computer screen, and uttering a dramatic statement about evidence from a crime—the hair came from the victim, the DNA matches the suspect,
the white powder is cocaine, and so on. At this writing, the three versions of CSI
on television are among the most popular shows ever. Why the sudden popularity?
After all, forensic science has been practiced in one form or another for over five
thousand years. An important reason is that recent serious cases have occurred in
the U.S. and elsewhere where forensic science has played a major role. Jon Benet
Ramsey, O. J. Simpson, Theodore Bundy, the Green River Killer have all exploded
onto the headlines in recent years and forensic science has played an important part
of all of them.
People all over the world are fascinated by crime, its investigation, and its solution. People enjoy using clues to solve puzzles and problems. They are concerned
with violent crime and want to do something about it. All of these factors feed into
the popularity of forensic science. The major impact of this growing field seems to
have been on women. Today, more than 75 percent of all students in forensic science
education programs in the U.S. are women and this trend seems to be the same in
other countries such as Australia and England.
In some ways, for women and men alike, the interest in “whodunit” isn’t a
new phenomenon. For more than a century, people have been fascinated by the
exploits of Sherlock Holmes, the clever detective penned by Arthur Conan Doyle.
As far back as the early days of TV and cinema, there have been shows about
crime, policing, lawyers, and criminals. In recent years, the focus has shifted to
forensic science. Although some people decry CSI and other similar shows about
forensic science, the fact is that they have raised the public conscience about
science and its role in crime solving. Forensic science provides a unique way of
teaching students the principles of science as well as problem solving, critical
thinking, oral and written communication skills, and the role of bias in the practice of science.
Is the portrayal of forensic science and scientists in the media accurate? What
do forensic scientists really do? How is forensic science presented in court and what
effect does it have on juries as they deliberate the fate of the accused? This is what
this book is all about. You will learn about the various branches of forensic science,
how crime labs are organized, how evidence is collected and analyzed, and how scientific testimony is presented in court.

What Is Forensic Science?
In the ancient Roman Empire, the Senate used to conduct its meetings in a public
place called the forum. Anyone who wanted to could listen to the great debates of
the day and watch the government in action. The key here is that the forum was a
place where everyone could come and observe. The term “forum” is Latin for “public”
and “forensic” is derived from that term. “Forensic science” implies, then, something about science and the public. In the broadest sense, forensic science can
be defined as the methods of science applied to public matters. By this definition,
forensic science doesn’t necessarily have to do with crime, but the term has evolved
in modern times to refer to the application of science to court or criminal matters.

Introduction to Forensic Science 7

Most forensic scientists work in the criminal area of the justice system, although
civil cases are an important component of forensic science. In this book, focus will
be on the applications of science to criminal matters.

Depth and Breadth of Forensic Science
If “forensic science” refers to science applied to criminal and civil law, one may
wonder which of the sciences are actually forensic sciences? The answer may surprise you. Any science can be a forensic science if it has some application to justice. Think about how many different areas of science could potentially be brought
to bear on solving crimes. Many medical, physical, and biological sciences have
forensic applications, as do math, business practices, sociology, and psychology.
The list is nearly endless. The most common areas of science that have forensic
applications are described below. This will give you an idea of the “big tent” that
is forensic science.

Forensic Science v. Crime Scene Investigation
There is a good deal of confusion about the relationship between forensic science
and crime scene investigation. Part of this may be due to TV shows such as CSI
that blur the distinctions between them by depicting the people who collect evidence from a crime scene as the same people who analyze the evidence in the crime
lab. In reality, these are different functions, but with some actual overlap. Crime
scene investigators are usually, but not always, police officers trained for and then
assigned to the crime scene unit. They learn how to recognize evidence, protect it
from contamination, collect it properly, thoroughly document its location and condition, and maintain a chain of custody to help authenticate the evidence when it
gets to court. Crime scene investigators have a science education background, but
many do not. Some are also trained in procedures that could be considered forensic
science because they involve preliminary (or complete) analysis of some types of
evidence. Examples include preliminary analysis of suspected illicit drugs (called
“field tests”), collection and analysis of fingerprints, and documentation and analysis of bloodstain patterns. To the extent that they analyze this evidence and reach
scientific conclusions and then testify in court as experts, these investigators would
be considered forensic scientists and this part of their job would be forensic science.
This type of activity among crime scene investigators is relatively rare but still common enough to bear mention. Under normal circumstances, the job of crime scene
investigator stops when the evidence is delivered to the laboratory where the actual
work of the forensic scientist begins. Most people in the forensic science field do
not consider crime scene investigation activities to be part of forensic science in spite
of the fact that many crime scene units are administratively within the lab structure and that forensic scientists are increasingly going to some crime scenes to help
with investigations.

Criminalistics
The term “criminalistics” was first coined by Paul Kirk, considered by many to
be the father of forensic science in the United States. In some quarters, criminalistics is synonymous with forensic science and the two terms are often used
interchangeably. In California, forensic scientists are often officially called criminalists. The term can be used to describe the comparative forensic sciences such

8

Forensic Science: The Basics, Second Edition

as fingerprints, questioned documents, firearms, and tool marks. Most commonly,
however, criminalistics refers to the myriad types of physical evidence generated
by crime scenes. This includes illicit drugs, blood and DNA, fire and explosive residues, hairs and fibers, glass and soil particles, paints and plastics, fingerprints,
bullets, and much more.
A Bit of History: Paul Kirk
Paul Leland Kirk was a chemist and forensic scientist. He held a Ph.D. in biochemistry from the University of California at Berkeley. He started his career at
Berkeley in the biochemistry department and became interested in forensic science when authorities asked him to examine evidence from a rape case. Because
of his interest and experience in microscopy, he was asked to head up the new
Berkeley criminology program in He subsequently worked as a microscopist on the Manhattan Project where he helped isolate fissionable material for
making bombs. In , he returned to Berkeley and headed up the technical
criminology major program and served as head of the criminalistics department.
Kirk is best known professionally for his work in the Sam Sheppard murder case.
In this case, Dr. Sam Sheppard was falsely accused of murdering his wife. He
escaped from custody and helped the police find the “one-armed” man who committed the crime. This case was the basis for The Fugitive, a book, TV show, and
movie. Kirk examined bloodstain patterns from the scene and his subsequent
report and testimony at the second trial helped free Sheppard. Today, Kirk’s
legacy lives on in the Paul Kirk Award, the highest award given by the criminalistics section of the American Academy of Forensic Sciences.

Pathology
When some people think of forensic science, they envision dead bodies and autopsies. Not all of forensic science is like this, but forensic pathology is. The forensic
pathologist is a medical doctor who first specialized in pathology and then in forensic pathology. Forensic pathologists determine the cause and manner of death in
cases where someone dies under suspicious or other circumstances as prescribed by
state law. Many forensic pathologists work for state or local medical examiners or
coroners. These are appointed or elected officials who must decide when a medicolegal autopsy (an autopsy in a case of suspicious death or homicide) is needed and they
must sign death certificates that indicate the cause and manner of death. Medical
examiners and coroners don’t usually perform the autopsies themselves. They
employ forensic pathologists to do this. Forensic pathology is discussed in detail in
Chapter If you would like to learn more about medicolegal autopsies, check out
www.nlm.nih.gov/ex hibition/visibleproofs/e ducation/medic al/index.html.

Anthropology
A Bit of History: An Early Case in Forensic Anthropology
In , a Boston physician named Dr. George Parkman was murdered. The
suspect in the case was John Webster, a professor of chemistry at Harvard who
was in considerable debt to Dr. Parkman. The modus operandi of the crime was
that Professor Webster incinerated Dr. Parkman. When investigators searched

Introduction to Forensic Science 9

through the ashes, they found some remains of skull and some badly damaged
remains of dentures. The prosecution retained several experts in osteology
and physiology who examined the bone fragments. They determined that they
belonged to a white male, about 50 to 60 years of age, about 6 feet tall. Dr.
Parkman was 60 years old and 5 feet 11 inches tall. In addition, experts matched
the dentures to Dr. Parkman (Berryman, 13 Crime Lab Digest, ).
Forensic anthropologists work with skeletal remains. They identify bones as being
human or animal. If animal, they determine the species. If human, they determine
from what part of the body the bone originated. If they have the right bones, gender
can be determined as well. Sometimes age can be approximated and racial characteristics determined, and even socioeconomic status may be estimated. If there is
an injury to a skeleton or major bones, the anthropologist can help determine the
cause of the injury or even death. Forensic anthropologists do other things besides
identifying bones. They also work closely with skulls. It is possible to literally build
a face onto a skull, using clay and wooden or plastic pegs of various sizes. Using
charts that give average tissue depth figures for various parts of a face, an anthropologist constructs a face and then makes judgments as to that person’s eye, nose
and mouth characteristics. Facial reconstruction can be useful in helping to identify
a missing person from the face built around a recovered skull. It is also possible for
a forensic anthropologist to superimpose a skull onto a picture of a face to see if they
are one and the same person. This is not usually definitive, but can be quite helpful in establishing the identity of a skull. Forensic anthropology is discussed in
detail in Chapter

Odontology
“Odontology” is a synonym for dentistry. You may be curious about how a dentist
could be a forensic scientist, but actually there are several ways. A few years ago
in Pennsylvania, a burglar broke into a house and ransacked it for valuables while
the owners were on vacation. During his foray, he got hungry and rooted through
the refrigerator for something to eat. He found a hunk of Swiss cheese and took a
bite. Later, he was arrested, trying to “fence” (sell on the black market) the stolen
merchandise. When the police investigated the home looking for clues that would
tie him to the scene, they found the cheese. A forensic dentist made a cast of the bite
mark in the cheese and matched it to an impression of the burglar’s teeth.
The most famous case where bite marks were crucial evidence involved Theodore
Bundy, suspected of killing more than thirty young women in his career as a serial
killer. He operated first in Washington, Utah, and Colorado and then moved to
Florida. During his last homicide, he bit his victim on her buttock after strangling
her. A forensic dentist was able to match Bundy’s teeth to this bite mark. He was
executed in Florida for this murder in
Key Figures in Forensic Science: Ted Bundy
Ted Bundy was born in in Vermont in a home for unwed mothers. His
father’s identity was not conclusively determined and he was raised by his grandparents. He later moved to Washington state where he went to high school.
Before he graduated from high school, he was a thief and shoplifter and known
for being quite introverted and socially awkward. After graduating from high
school, he went to the University of Washington and ultimately earned a degree

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Forensic Science: The Basics, Second Edition

in psychology. By all accounts, he was an honors student and well liked by his
teachers. He subsequently began law school there, but dropped out.
Some experts, including those who knew Bundy, believe that he started his
killing spree during his early teens. At one point, he told his attorney that he
attempted his first kidnapping when he was in college. The earliest murders that
could conclusively be attributed to him occurred when he was He started a
string of brutal killings of young, white women in Washington and Oregon and
then Utah and Colorado. He was caught in Colorado but escaped twice from jail
and fled to Florida where he resumed his rampage after more than two years.
His last murders took place in Tallahassee at a sorority house. It was these
murders for which he was tried and ultimately executed. Crucial evidence in
these murders was a bite mark that he left on the buttock of one of his victims.
At his trial, a forensic odontologist testified that he matched the bite mark to a
cast made of Bundy’s teeth. Several jurors told the media after the trial that this
was the crucial piece of evidence against Bundy. This was the first instance in
the U.S. where bite marks had been used as evidence in this fashion. It should
be noted that, as Bundy’s execution date neared, he tried to buy time or get his
sentence commuted to life in prison by offering to tell families where the bodies of some of his victims were in exchange for their writing letters to the judge
asking for clemency. Not one family agreed to this and he was electrocuted in
January of
Forensic odontologists can also be very helpful in identifying the remains of victims
of mass disasters such as airplane crashes. Sometimes bodies are so badly burned
or dismembered the only way to identify the remains is by using dental records.
Postmortem dental records are taken and matched to x-rays taken before death.
Finally, forensic dentists may play a role in child or other abuse cases. A forensic
dentist can often tell whether facial injuries received by a person were the result of
falling down a flight of stairs or if they were due to blunt force injury such as striking
the person with a fist or other object. Forensic odontology is covered in more detail
in Chapter

Engineering
Forensic engineers can be valuable in cases where something has gone wrong with a
mechanical or structural entity or in cases of automobile crashes. A few years ago, a
balcony collapsed in the lobby of a Hyatt hotel in Kansas City. Many people were on
the balcony at the time watching a rock concert going on in the lobby several stories
below. Questions arose about why the balcony collapsed. Forensic engineers were
called in to examine the structural remains of the balcony and the concrete that
fell. They concluded that the construction of the balcony was faulty and contributed
to its failure. Failure analysis is one of the major contributions that forensic engineers make to the justice system. Figure  shows the damage to the Hyatt hotel in
Kansas City after the walkway collapse.
The majority of the work of forensic engineers is in the investigation of traffic
crashes. Accident reconstruction is used to determine speed of travel, direction of
impact, and who was driving the vehicle at the time of the crash. Insurance companies and police departments use forensic engineers extensively in traffic incident
investigation.

Introduction to Forensic Science 11

Figure  Wreckage of the collapsed Hyatt Regency Hotel in Kansas City. Associated Press file
photo (with permission).

Entomology
When a person dies and the body is exposed to the elements, who (or what) gets there
first? It’s not witnesses or detectives, but flies—more specifically, a species called
the blow fly. During the bombing of the Murrah Federal Building in Oklahoma City
(Terry Nichols and Timothy McVeigh were convicted of the bombing), bodies were buried in the tons of rubble from the collapsed building. Investigators literally followed
the flies into the rubble in order to locate many of the bodies. Female blow flies and
other insects lay their eggs in decaying flesh and different insects do this at different
times. Other insects such as beetles and wasps attack and feed off the insects and the
eggs. Depending on temperature and other environmental factors, this parade of visitors takes place at surprisingly consistent time intervals. By inspecting the corpse,
forensic entomologists can give a pretty good estimate of the elapsed time since death
and determine whether the body has been at a site for many hours or several days.
In addition to the postmortem interval, there is other information that can be
gained from studying insects feeding on a corpse. If a person has been poisoned, the
flies and other insects will ingest some of the poison. A toxicologist can capture some
of these critters, chop them up, and extract the poison and identify it. There are also
cases where a person took cocaine and then died. Some of the maggots on the body
became abnormally large in size owing to their ingestion of the cocaine. Forensic
entomology is covered in detail in Chapter

Behavioral Forensic Science
Forensic psychiatry and psychology have been long contributors to the forensic sciences. As long as there has been crime, people have wrestled with the concept of
responsibility. Our laws and those of most other countries have long had provisions
for how people who commit crimes and have diminished capacity are treated. If a
person is truly insane, can she be held responsible for committing a crime? Although
the definitions vary as to what constitutes responsibility, insanity, etc., it falls to
forensic psychiatrists and psychologists to examine defendants and render expert
opinions to courts. There are real differences between psychiatrists and psychologists. Psychiatry is a medical specialty attained by medical doctors. Psychology is a
behavioral science that does not involve medical training. Both have a role to play
in determining responsibility for committing crimes.
Forensic psychologists play other roles in the criminal justice system. Some crime
investigations include a component of psychological crime reconstruction. Serial killers

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Forensic Science: The Basics, Second Edition

SNIPER UNDER COVER IN CAR
Holes drilled in
rear of car for
muzzle and
telescopic sights

THE CAR
blue Chevrolet Caprice
Used in 11 of 14 shootings say police
Boot converted to sniper’s perch

Figure   A drawing of a car outfitted so that a sniper can fire a weapon out of the back without
being detected. This is similar to the set up used by the DC snipers.

and others who commit multiple crimes develop habits and traits that show up time
after time as they commit crimes. Discovering and understanding these patterns can
help lead investigators to the right suspect. Specially trained forensic psychologists
can examine a series of crime scenes and develop theories about the type of person who
committed the crimes. It must be noted that this work is much more of an art than
a science and is often fraught with uncertainties. A case in point is the Washington
D.C. sniper case of October Forensic psychologists and criminal investigators
initially determined that the killer was a young, white male. As it turned out, the killers were two black males. Such attempts to determine a profile of a serial killer can
be very difficult, even if there are many incidents to draw on for data. Figure  is a
drawing of the car similar to the one the killers used when killing their victims.
Psychological profiling has also been used in other criminal and civil areas. For
example, the Transportation Security Administration (TSA) uses forensic psychologists to create profiles of what a likely airplane hijacker might look like or behave
like so security checkpoint officials can subject people who meet the profile to additional screening. This has been going on for many years in one form or another. The
Department of Homeland Security has a similar program for border guards to help
spot potential terrorists.
There are other types of behavioral forensic scientists. Some study interrogation and investigation techniques such as polygraph instruments to determine their
accuracy and usefulness in criminal and civil investigations. Others do research in
developing new areas of interrogation and deception detection.

Computer Forensics
Computer forensics is sometimes called digital forensics as well as by other
descriptors. Computers have become very important in crime today, both as instruments of crime and in helping to solve crime. Many criminals and criminal enterprises conduct much of their business and keep their business records on computers.
Sometimes these records are highly encrypted. When caught, criminals often try
to erase or physically destroy the data to prevent it from being used against them.

Introduction to Forensic Science 13

Computer forensic scientists and engineers study ways to recover data even from
smashed hard disk drives. They also learn how to handle a computer found at a
crime scene, especially one that is turned on. Computers are also used to steal identities from people and merchandise from companies. They can be used to disrupt
entire networks and hack into otherwise secure, private websites. Computers can
also be used to help solve crimes. They can track people down, store incriminating
data that can be used against criminals, and help test and improve computer security. Computer forensics is one of the fastest-growing areas of forensic science and
will continue to grow in the future.

History and Development of Forensic Science
When did people actually invent forensic science? When was science first applied to
answering questions about crimes or civil issues? Some baby boomers remember the
Quincy TV show as the first time they saw forensic science in action. Twenty- and
thirty-somethings think of the O. J. Simpson case as the beginning of the use of
science to solve real crimes. Today many people think of CSI as the birth of forensic
science. In reality, some aspects of forensic science have been at least recognized for
centuries. An excellent outline of the history of forensic science in the form of a timeline has been published by Norah Rudin and Keith Inman and can be found on the
Web at www.forensicdna.com/Timelinepdf. The earliest milestones in all
areas are covered first and then gradually brought up to date. In this chapter, data
from the timeline referenced above will be used to illustrate the history of forensic
science, highlighting three important examples: fingerprints, crime laboratories,
and blood analysis.
As in many other fields of knowledge, the Chinese were the first to discover the
value of forensic science in identification. They were the first to use fingerprints to
identify the owners of objects such as pottery, but had no formal classification process. In later centuries, a number of scientists, such as Marcello Malphighi, noted
the presence of fingerprints and that they had interesting characteristics, but didn’t
make any connection to personal identification. The first person to recognize that
fingerprints could be classified into types (nine major kinds) was Jan Purkinje, a
professor of anatomy. In , a Scottish physician named Henry Faulds published
an article in the journal Nature that suggested that the uniqueness of fingerprints
could be used to identify someone. This was quickly followed in the s by Frances
Galton, who published the first book on fingerprints; Juan Vucetich, who developed
a fingerprint classification system that is still used today in South America; and Sir
Edward Henry, who developed the fingerprint classification system that has been
adopted in the United States and Europe.
The development of a forensic science infrastructure including crime labs is much
more recent and quite interesting. For example, the first detective force was developed in France, The Sûreté of Paris by Eugene Vidocq in In , President
Teddy Roosevelt established the FBI, but the FBI lab was not established until
The first crime laboratory was established in France in by Edmund Locard,
a professor of forensic medicine. He later espoused his famous Locard Exchange
Principle, which will be discussed in the next chapter. In the United States, the first
crime laboratory was established by August Vollmer, chief of police in Los Angeles.
The first journal devoted to forensic science was begun by Calvin Goddard and
his staff in at the newly formed Scientific Crime Detection Laboratory on the

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Forensic Science: The Basics, Second Edition

campus of Northwestern University. Initially called the American Journal of Police
Science, the name was later changed to the Journal of Criminal Law, Criminology,
and Police Science. In , Paul Kirk established the first university-based forensic
science program at the University of California at Berkeley. It was called Technical
Criminology. Dr. Kirk is generally considered the father of modern forensic science in
the United States. In , the American Academy of Forensic Science (AAFS) was
founded in Chicago. The AAFS is the largest forensic science society in the world
and has members from many different countries. The Academy began publication of
the Journal of Forensic Sciences, the professional journal of forensic science, shortly
after AAFS was founded.
The realization that blood and bodily fluids had the potential for being important
evidence in criminal investigation is an old idea. Bloody palm prints were used as
evidence more than a thousand years ago in Rome. In , Ludwig Teichmann
developed the first of a number of crystalline tests still used today in the characterization of blood. His test detected the presence of hemoglobin. The German scientist Schönbein developed the first presumptive test for blood. It takes advantage
of the ability of hydrogen peroxide to react with hemoglobin. This was in In
, Karl Landsteiner made major breakthroughs in the analysis of blood when
he determined that there are actually four types of human blood. This became the
basis for the ABO blood typing system and set the stage for all further work in
serology. Landsteiner won the Nobel Prize for his work in Max Richter took
Landsteiner’s results and adapted them to blood stains, such as those found in crime
scenes. Fifteen years later, Leone Lattes, a professor in Italy, developed a test to
determine blood type in the ABO system and wrote a book about how to type dried
stains. There were a number of advances over the next thirty years, culminating in
the work of Sir Alec Jeffreys of the University of Leicester. In , Jeffreys used a
technique called DNA fingerprinting to solve a double murder case in England, the
first case solved by DNA analysis. The year before, Kary Mullis developed the polymerase chain reaction (PCR), which is the basis for all DNA typing in forensic cases
today. He also won the Nobel Prize for his work.

What Is a Forensic Scientist?
Since practically any science can be a forensic science at times, many scientists can
be forensic scientists. It is partially a matter of what they do in their jobs, but also a
matter of training and education. Forensic pathologists, for example, are educated
as physicians and then trained as pathologists. After that, they can get specialized
training in the forensic aspects of pathology and become certified as forensic pathologists. This assures that they will have the proper education, training, and licensure
to practice pathology on medicolegal cases. There is, however, a critical shortage of
certified forensic pathologists in the U.S. and many medicolegal autopsies are performed by pathologists who have no forensic training. Are they forensic pathologists
by virtue of their performing forensic autopsies? Most pathologists would agree that
they are not. The situation is somewhat different for forensic anthropologists, odontologists, and entomologists. There are a few forensic anthropology degrees, but
essentially none in odontology or entomology. There are certifications for all three
that result in a designation as forensic anthropologist, odontologist, or entomologist.
The fact is, however, that most of what would be considered forensic cases in these
areas are performed by noncertified but professional scientists. With increased

Introduction to Forensic Science 15

attention being paid to these forensic sciences, questions of who should be performing forensic analysis become more important.
The majority of forensic scientists work in crime laboratories on the local, state,
or national level. Most forensic science laboratories are associated with law enforcement agencies such as the Detroit Police Department Crime Lab, Indiana State
Police Forensic Lab, and FBI Lab. Although early in their history most of these laboratories were staffed by enlisted officers, special agents, and the like, today increasing numbers are civilians who have no police duties. One of the reasons is that as
forensic science has become more sophisticated and rigorous, it has been harder to
find scientifically trained police officers. The other reason is that police departments
want to put more officers on the street and are transferring enlisted analysts out of
the lab and into law enforcement duty.
In a crime laboratory, forensic scientists have two major duties: to analyze evidence and to testify in court. Forensic science laboratories behave in a reactive role.
When a crime is committed, the crime scene unit collects the evidence and turns it
over to the police investigators (sometimes detectives) who then bring it to the crime
lab. In some cases, the crime scene investigation unit may turn evidence directly
over to the lab. The lab scientists then analyze the evidence. They generally do not
have much input into what evidence is collected, although there may be occasions
where a forensic scientist asks the police to collect additional items of evidence for
comparison or further analysis. In recent years, there has been an increasing trend
toward having forensic scientists attend at least some crime scenes. For example,
the Michigan State Police Forensic Science Division forms teams of forensic scientists that are called on to help process serious crime scenes such as those in which
there is a dead body. These scientists work along with the police CSI team to help
process the scene and collect evidence.
The other major duty of forensic scientists is to testify in court. In the United
States criminal justice system, there are basically two types of witnesses who testify in court: lay and expert witnesses. A lay witness is someone who is not an
expert but has something to contribute to help the judge or jury determine the guilt
or innocence of the accused. This person may have been an eyewitness to a crime,
a victim or someone who knows something about the suspect or the crime. Such
witnesses are supposed to testify only to what they have perceived with their five
senses: touch, taste, smell, sight, and hearing. They are not to give their opinions. It
is the jury’s job to make conclusions about the evidence presented to them, not the
witness. For example, if a witness offers testimony that the driver of a car involved
in a traffic accident was drunk, that conclusion would not be permitted in court.
Being drunk in the motor vehicle code sense requires an expert finding of sufficient
alcohol exceeding the legal limit in the driver’s body.
The other type of witness in a court is an expert witness. This is a person who
has knowledge and/or skills, derived from education and/or experience, that qualifies him or her to take a set of facts and reach conclusions not attainable by the
average person (the judge or jury). Most people think of experts as being Ph.D. scientists or doctors and, although many of them are, other experts may derive their
expertise from experience rather than formal education. For example, suppose that
a man is driving down a mountainous road when his car’s brakes fail. He crashes
his car and dies. The police investigator would want to know why the brakes failed.
Were they old and in need of repair? Were they installed improperly by a mechanic?
Were they tampered with so that they would fail purposefully? Each of these explanations would call for a different response by the justice system. If someone were
put on trial for killing the driver, it would not be prudent to have the jury go to the

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Forensic Science: The Basics, Second Edition

garage where the wrecked car was stored and have the jurors inspect the brakes to
see what caused them to fail. Most jurors would not have the knowledge to inspect
the brakes (the facts) and draw conclusions (the opinions) about how they failed. An
expert brake mechanic should be called on to inspect the brakes and determine the
cause of their failure. This individual can give testimony as an expert about the
failure of the brakes.
Whether a trial is by jury or judge, it is the judge’s responsibility to decide whether
expert testimony is needed and who is qualified to offer it. Even if a forensic scientist has testified hundreds of times, he or she must be requalified as an expert for
every trial. It is important that the expert explain complex scientific or technical
principles in a language that a jury can understand. Forensic scientists must be
equally competent in the trial part and the scientific part of their jobs.

So You Want to Be a Forensic Scientist
So now you know what forensic scientists do and where they work, but what does it
take to be one? This depends on what type of forensic scientist you want to be and
what type of work you want to do. Becoming a forensic scientist requires both education and training. We shall discuss a few of the more common areas of forensic
study. Figure  is a chart that summarizes selected forensic science careers, optimal education, and job markets.
• Crime lab forensic scientist. Entry level requirements for a crime lab
scientist position are usually either a bachelor’s degree in a science such as
chemistry, biology, or forensic science with a year or two of experience or a
master’s degree with less experience. (The job market is very competitive and
a master’s degree is becoming the preferred degree.) There are more than
forensic science education programs in the U.S. today and more than
in the United Kingdom—that’s a lot Many of these so-called forensic science
degrees are not science-based or not rigorous enough to properly prepare students for careers in forensic science. A few years ago, the American Academy
of Forensic Science and the National Institute of Justice developed a set of
standards for bachelor’s and master’s degree forensic science programs and
created the Forensic Science Education Program Accreditation Commission
(FEPAC). Information can be found on the website of the American Academy
of Forensic Sciences: www.aafs.org.
• Forensic pathologist. To become a forensic pathologist, you first need to
graduate from college with an excellent academic record. Then you must
graduate from medical school, requiring another four years. After medical
school, you complete a residency in pathology, which takes an additional four
years. Finally, an additional residency in forensic pathology is recommended
in order to become certified. This takes another year to complete.
• Forensic anthropologist. Few crime labs can afford to hire a forensic
anthropologist full time. If you have another area of specialization such as
trace evidence or DNA typing, you may be hired by a crime lab and then
handle anthropology cases as they come up. Another way of getting into the
field is to obtain a Ph.D. in physical or forensic anthropology and teach and
do research at a university; then local crime labs would come to you for your
services as needed.
• Forensic odontologist. This is similar to the route for a forensic pathologist except that you would complete dental school instead of medical school.

Determine cause and manner of death
in suspicious or unattended deaths

Excavate crime scenes and analyze
skeletal remains
Analyze bite marks, facial injuries
and identify human remains from
dental work
Reconstruct vehicle accidents,
structural failure analysis, explosion
analysis, electrical systems
Determine role of computers in crime
Reconstruct media devices and
computers
Track down criminals who hack into
sites and steal identities

Forensic Pathologist

Forensic Anthropologist

Forensic Odontologist

Forensic Engineer

Computer Forensic Scientist

Most forensic engineers are in private
practice. Need for experienced engineers
is pretty large.
Some are in private practice. Many work
for colleges as teachers/researchers and
do forensic work on the side.

PhD in computer science or computer
engineering, lots of experience

Few people make a living strictly on
forensic dentistry. Most have conventional
dental practices and do forensic work on
the side. Job market is small.

Most forensic anthropologists teach at
colleges and do forensic anthropology on
the side. Job market is small.

Excellent. There is a nationwide, critical
shortage of certified forensic pathologists.

Robust but spotty
More than new forensic scientists
needed

Job Market

PhD in engineering, lots of experience

BS or BA degree + 4 years of dental
school. No residencies in forensic
dentistry

PhD in physical or forensic
anthropology

BS or BA degree + 4 year medical
school degree + 3–4 year residency
in pathology + 1–2 year residency in
forensic pathology

At least a BS degree in science
MS degree preferred

Optimal Education

Figure   This chart shows the types of careers and best educational preparation for various areas of forensic science.

Analyze scientific evidence
Testify in court

Job Description

Crime Lab Forensic Scientist

Career

Introduction to Forensic Science 17

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Forensic Science: The Basics, Second Edition

There are few (if any) residencies in forensic odontology, therefore you would
have to work with police departments on an as-needed basis.
• Forensic engineer. This career requires education in engineering—and
the more the better. Usually, experts in forensic engineering need to have
a Ph.D. Most forensic engineers have their own private companies that are
hired by prosecutors or defendants.
• Computer forensic scientist. There are few education programs that turn
out computer forensic scientists. People who work in this area invariably have a
strong interest and educational background in computer science and engineering. Their designation as computer forensic scientists arises from the types of
cases that they work on or the type of research and teaching they do.
• Related careers. Not everyone wants to be a forensic scientist in a laboratory. Some people decide they want to work in a career that makes use of
their strong science background and perhaps a forensic science education.
There are a large number of related careers one could consider. If you decide
to be a lawyer, a science background can be very handy in the field of patent law. Many patents require practice and skill in reading and digesting
sometimes complicated journal articles and books. These particular skills
are highly developed in a science education. Environmental forensic science is becoming a major area of environmental study. Scientists work for
environmental analytical laboratories determining pollution levels in air,
water, and soil and can help companies comply with environmental laws or,
conversely, help government agencies track down and prosecute polluters.
The pharmaceutical industry is very interested in people with strong analytical chemistry backgrounds. Many forensic science educational programs
teach the chemistry and analysis of illicit drugs—information that can be
valuable in a career in pharmaceutical chemistry. The insurance industry
is also interested in employing scientists, including those with forensic science backgrounds. They investigate fires, explosions, traffic accidents, stolen
automobiles, and other property incidents to help determine if a crime was
committed or a covered loss occurred.

Career Information
The websites of any of the federal agencies listed in the section on the organization
of federal forensic science labs will provide information about how one joins that
organization as a forensic scientist. In addition, one can check the website of the
state or local law enforcement agency where crime labs are housed for information
about obtaining employment.
General job and career information in forensic science can be found at the American
Academy of Forensic Sciences: www.aafs.org. The Academy is the major national organization for forensic scientists. There is a section on its website that posts job openings
in the field. The Academy also provides information on careers in forensic science.
Information about careers in particular areas of forensic science can be found on
the websites of the specific association or society. A few of them more common ones
are listed below.
• American Academy of Forensic Sciences: www.aafs.org
• National Association of Medical Examiners: www.thename.org

Introduction to Forensic Science 19

• Society of Forensic Toxicologists: www.soft-tox.org
• American Society of Questioned Document Examiners: www.asqde.org
• American Board of Forensic Anthropology: www.csuchico.edu/anth/ABFA
• Forensic Entomology: www.forensic-entomology.com
• Association of Firearm and Tool Mark Examiners: www.afte.org/index_
forum.php
• American Society of Forensic Odontology: www.forensicdentistryonline.org/
new_asfo/newasfo.htm

The United States Forensic Science System
There are approximately four hundred forensic science laboratories in the United
States. Most of them are public labs supported by a unit of federal, state, or local
government. Others are private labs. A laboratory may be full service, running
tests in all of the major areas of forensic science. Others may conduct only the most
common examinations of evidence such as drugs, firearms, and fingerprints. The
federal government and all fifty state governments administer some form of laboratory system or network.

Federal Forensic Science Laboratories
Most people are familiar with the FBI laboratory and many people think that
it is the only crime lab run by the United States government. The fact is that
there are many federal laboratories and they are located within several cabinet
departments. Figure  is a diagram of how the federal forensic science labs are
arranged.

Dept. of Interior

Dept. of Treasury

Dept. of Justice Dept. Homeland Security

Internal Revenue

Secret
Service

U.S. Postal Service

Customs

Fish & Wildlife
Postal Service
FBI

DEA

ATF

Figure   An organizational chart of the major federal forensic science laboratories.

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Forensic Science: The Basics, Second Edition

Figure   The new FBI laboratory in Quantico, Virginia.

The Justice Department
Most of the federal crime labs are located within the Department of Justice. They
are under the administrative control of the Attorney General of the United States.
The FBI Laboratory
www.fbi.gov
The Federal Bureau of Investigation laboratory is in Quantico, Virginia. It is supported by the Forensic Science Research and Training Center (FSRTC), also located
in Quantico. The FBI lab is one of the best known and most prestigious forensic
science laboratories in the world. The FBI lab supports the law enforcement and
antiterrorism missions of the FBI by analyzing evidence generated by these activities. The FBI lab also processes evidence sent in by state and local law enforcement
agencies or crime labs. Personnel from the FBI lab also travel to foreign countries to
help indigenous law enforcement agents solve crimes against United States citizens
and those with global implications. Figure  is the FBI Laboratory in Quantico,
Virginia.
The Drug Enforcement Administration (DEA)
www.usdoj.gov/dea
The DEA has a network of regional laboratories located in Washington, D.C.,
Miami, Chicago, Dallas, San Francisco, and New York. They are supported by the
Special Testing and Research Lab in Virginia. The DEA analyzes illicit drugs seized
by DEA agents and by task forces made up of state or local drug agents working
with the DEA. It also works with foreign countries to help eradicate illicit drugs
or help prevent their importation into the United States. The DEA shares training
facilities with the FBI in Quantico, Virginia.
The Department of the Treasury
Most people are surprised to find that the Department of the Treasury has crime
labs, but in fact it has several. These labs have definite areas of responsibility.
The Bureau of Alcohol, Tobacco, and Firearms (BATF)
www.atf.treas.gov
The BATF has a number of missions supported by a network of its three laboratories located in Beltsville, Maryland, Atlanta, and San Francisco. As the name of the
agency suggests, agents of the BATF are in charge of making sure that all alcohol

Introduction to Forensic Science 21

produced in or imported into the United States has the proper tax stamp indicating
that the correct taxes have been paid. This is a revenue function that explains why
the agency is in the Department of the Treasury. Likewise, the BATF has similar
functions in the tobacco industry to ensure that the proper taxes have been paid
on cigarettes and that contraband tobacco products such as Cuban cigars are not
imported illegally. The firearms mission is a bit different. The Bureau is charged
with making sure illegal firearms are not produced, imported, or exported and that
the proper taxes and duties are paid on legal weapons. In addition to the areas mentioned above, BATF labs employ some of the world’s leading experts in fire and explosive analysis who work with law enforcement agencies all over the world. The labs
also have expertise in trace evidence, fingerprints, and questioned documents.
The Secret Service
www.ustreas.gov/usss/index.shtml
When most people think of the Secret Service, they picture serious, dark-suited people guarding the president of the United States and other domestic and international
VIPs. Certainly the protective function is the most visible part of the Service, but not
the only one. The Secret Service maintains a laboratory in Washington, D.C. that
has several functions. It supports the protective services of the agency by continuously developing methods that counter attempts to harm the people that the Service
is guarding. In addition, the agency is charged with preventing attempts at counterfeiting money and credit cards. This explains why the agency is in the Department
of the Treasury. As one would expect, there are leading experts in counterfeiting and
questioned documents as well as trace evidence employed in the Secret Service lab.
The Internal Revenue Service (IRS)
www.irs.gov
No discussion of the Department of the Treasury would be complete without
mention of the IRS. The IRS is charged with making sure that everyone pays a fair
share of taxes according to the law and there are many IRS agents who do that job.
They are supported by a laboratory in Chicago, whose major expertise lies in the
area of questioned documents. This lab utilizes experts in handwriting, typewriting
and printers, inks, and papers. In addition to their analytical work, they carry out
numerous training activities for other agencies.
The Department of the Interior
www.lab.fws.gov
Wait, doesn’t the Department of the Interior take care of the national parks,
forests, and the environment? What do they need with a crime lab? Doesn’t the
FBI have jurisdiction over the parks and forests? Well, yes and no. The FBI lab
has a lot of experts, but none in wildlife biology and animal body parts. So in ,
the United States Fish and Wildlife Service established the world’s first and only
laboratory that specializes in wildlife forensic science in Ashland, Oregon. This lab
supports the enforcement activities of the fish and wildlife agents who patrol the
national parks and forests to help prevent poaching and hunting of endangered species. The lab also supports such efforts worldwide.
The United States Postal Service
www.usps.com/postalinspectors/crimelab.htm

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Forensic Science: The Basics, Second Edition

The United States Postal Service has an investigative arm that swings into
action when someone uses the mail to commit a crime. Such crimes can include
fraud, extortion, mailing anthrax or another dangerous substance to a government
official, illegal gambling, and other shady activities such as pyramid schemes, etc.
The United States Postal Service Laboratory in Washington, D.C. supports these
investigative activities. The emphasis here is on document analysis but other areas
of forensic science are also represented. These include trace evidence and fingerprints. The Postal Service is a quasi-governmental agency, meaning that it is private but is also government subsidized.

State and Local Forensic Science Systems
Each of the fifty U.S. states has a public crime lab system. The types and numbers of laboratories depend on the size and population of the state. For example,
Montana has one laboratory that serves the entire state, whereas California has
more than fifty public laboratories that operate at all levels of government. Every
state has at least one publicly funded forensic science laboratory. Governmental
units that administer crime labs include the state police, state highway patrol,
and Attorney General’s office. Some states have a consolidated laboratory division that may also include health department, toxicology and agricultural laboratories, and state medical examiner or coroner. For example, the Michigan State
police have seven regional laboratories throughout the state. The headquarters
lab in Lansing is considered full-service. It has all of the forensic science services
needed in the state including toxicology and behavioral analytical capabilities.
The other six labs provide the services that are in the most demand locally such
as drug analysis, trace evidence, firearms, and fingerprints. In addition to staterun laboratories, most states have some locally controlled facilities. In Maryland,
some of the larger counties have laboratories attached to the county police. In
California, the county sheriff in many large counties such as Los Angeles supervises an associated crime lab. Many large cities also have their own crime labs,
usually within their police departments. These include Detroit, New York City,
and Los Angeles.

Private Forensic Science Laboratories
Besides the federal, state, and local forensic science crime labs, there are numerous
private laboratories and their number is increasing. These range from one person
“niche” laboratories where one type of forensic science analysis is done, to nationwide
networks of labs that may handle several types of analysis. Many of the one-person
labs have been started by forensic scientists who retired from public laboratories.
They continue to ply their trade using prior contacts and word of mouth or print
advertising to build a client base. In the criminal arena, they usually work for defendants. The prosecutor has the use of the local or state public laboratory and in most
cases, the defendant cannot have access to the public facilities unless a judge specifically orders it. The private labs perform a service to the criminal justice system
by providing resources for defendants of crimes. A few private laboratories operate
in the public arena. For example, the Northern Illinois Police Crime Laboratory is
a private laboratory that contracts its services to the northeastern areas of Illinois
between Chicago and the Wisconsin border near Milwaukee. Another example is
Orchid Laboratories, which maintains a nationwide network of private DNA labs

Introduction to Forensic Science 23

that provide paternity testing services to public and private clients. Orchid performs the majority of noncriminal paternity testing in the United States each year.
One area where private labs seem to prosper is forensic engineering. Most professional forensic engineers are privately employed. They may work for the prosecutor,
the plaintiff, or the defendant. Some are connected with colleges or universities and
work as consultants on the side.

Other Forensic Science Systems
There is no standard organizational structure for a forensic science laboratory system. Each country has a system that best meets its needs. Organizational decisions
are based on historical precedent, population and its distribution, resources available, and levels and patterns of crime.

The United Kingdom
England and Wales have the Forensic Science Service (FSS) which includes a network of five regional crime laboratories. Originally, the police had access to the
FSS for free; the government supported the laboratories. The London police force
(Scotland Yard) had its own forensic science laboratory, the Metropolitan Police
Laboratory. In , the Forensic Science Service was complete revamped. The system adopted a pay-as-you-go process for all clients, including law enforcement agencies. Access to the system was also given to people accused of crimes at the same
costs borne by others. Later, the Metropolitan Police Lab was incorporated into the
FSS, making a total of six regional labs. Dire predictions of bankruptcy for the FSS
and for police departments that couldn’t afford the cost of what had been free forensic science services never materialized. The system adapted to the new technology
methods and is prospering today.

Australia
In a country the size of the U.S. but with 10 percent of the population, and where
most people live on the coast, one would expect a different type of forensic science
system. Each of the seven states in Australia supports some type of laboratory.
These range from single, full-service laboratories such as the Victoria Police Science
Centre near Melbourne, to the fragmented system in New South Wales, which uses
separate laboratories for firearms and fingerprints and for drugs and for chemical evidence. There is also a laboratory within the Australian Federal Police in
Canberra.

Colombia
A large South American country, Colombia’s judicial system has undergone major
changes in recent years. These include development of a forensic science laboratory system. There are four regional laboratories. Three are part of the federal law
enforcement system, which includes the Prosecutor General and the national police.
The fourth is a medical lab that supports the national medical examiner system.

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Forensic Science: The Basics, Second Edition
Organization of a Forensic Science Laboratory

Trace Evidence

Chain of Custody

Evidence Intake

Drugs

Toxicology

Evidence
Storage
Report

Lab Information System

Firearms

Questioned Documents

Fingerprints

Figure   Various sections of a typical forensic science laboratory.

The Organization of Forensic Science Laboratories
If you were to look at the inside of a forensic science laboratory it would, at first
glance, look like any other analytical laboratory. There are lots of instruments,
glassware, implements, and scientists in white lab coats and safety glasses. Like
most laboratories, forensic science labs are secure facilities that allow only very limited, escorted access to the public. But if you look a little deeper into a forensic science lab, you would see some things that you wouldn’t find in other types of scientific
labs. Many crime labs have few windows because windows are less secure. On the
other hand, questioned document examiners like to have windows in their sections
because they like to have natural light for document examination. The common
sections of a crime lab are listed below. Figure  is a chart that shows the major
sections of a typical crime lab.
In order for physical evidence to be admissible in a court for a trial, it must be
authenticated. That is, there must be proof that the evidence seized at the crime
scene is the same evidence that is now being introduced into court. There must be
a document that records who was in custody of the evidence at all times. The evidence must be kept in a secure container such that any attempt to breach the seal
would be evident. When the evidence container is opened, the person opening it
must reseal it with his or her initials and the date and time. All of these procedures
and the custody record collectively make up the chain of custody. An improper chain
of custody can be grounds to render evidence inadmissible.
Once impounded, the evidence will be put in a locked storage room. At some
point, the evidence will be assigned to one or more scientists for processing. Some
items of evidence require more than one type of analysis and decisions will have to
be made about which section analyzes it first. One of the important considerations
here is to make sure that one test done on the evidence does not ruin it for another
test. For example, suppose a gun is submitted for evidence containing the suspect’s
fingerprints on it along with some blood spots. The gun will have to be test fired so

Introduction to Forensic Science 25

a known bullet can be recovered for comparison. The blood will have to be removed
and tested for DNA. The fingerprints will have to be carefully lifted and compared
with the suspect’s prints. The order in which these tests are done is important.
When a decision is made, the evidence is turned over to the scientist, who uses a bar
code to log possession of the evidence.
1. The intake section. This is at the front of the lab. There will usually be
an intake officer who will log in the evidence to the laboratory information
system (LIMS). Typically, a bar code will be affixed to all of the pieces of evidence. Each item will have its own unique identification number.
2. The analysis area(s). This is the familiar laboratory setting. In most cases,
the scientists’ offices are located in a separate place away from the instruments. The area where the chemicals are kept is also isolated from the instruments because chemicals and electronics are not compatible. Each scientist
has a dedicated area of the lab for evidence handling. The instruments are
used by all of the scientists. In many larger laboratories, each scientist has
his or her own safe or other locked storage device for keeping evidence while
it is in his or her custody.
3. Other sections of the lab. Depending on the size and nature of the lab, other
sections are used by scientists from time to time. Some labs have a garage
where cars can be kept for inspection and searching. Many firearms sections
have huge stainless steel tanks full of water used to test-fire weapons for comparison with bullets or cartridges recovered from crime scenes. Some large
labs have collections of seized weapons as well as ammunition. If there is a
polygraph section of the lab, there will be one or more interrogation rooms.

Summary
Forensic science is the application of scientific methods to solving crimes. Any science can be a forensic science if it has an application within the criminal justice
system. The largest area of forensic science is criminalistics, which includes the
physical evidence commonly found at crime scenes. There are about four hundred
crime labs in the United States. Several departments in the federal government
have forensic science labs. These include Justice, Treasury, and Interior. Each state
has its own forensic science laboratory system. These include labs run by state or
local government.
Forensic scientists analyze evidence and testify in court as expert witnesses.
They may also go to some crime scenes where especially serious or notorious crimes
have been committed. Crime laboratories must be secure so that evidence can be
protected. There are many types of labs, but each has an intake section, an analysis
section, and a storage location for evidence.

Test Yourself
Multiple Choice
1. Which of the following federal departments does not have a forensic science
lab?

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Forensic Science: The Basics, Second Edition
















































a. Interior
b. Justice
c. Commerce
d. Treasury
e. All of the above have forensic science labs
2. Which of the following is generally not considered to be a forensic science?
a. Chemistry
b. Biology
c. Anthropology
d. Odontology
e. Sociology
3. California has about    percent of the crime labs in the United States?
a. 10
b. 50
c. 25
d. 12
e. 1
4. Which of the following is not part of forensic anthropology?
a. Matching teeth to a bitemark
b. Identification of skeletal remains
c. Building a face on a skull
d. Superimposition of the picture of a face onto a skull
e. Determining the gender of a skeleton
5. DNA typing is part of:
a. Forensic pathology
b. Criminalistics
c. Odontology
d. Engineering
e. Criminal investigation
6. If a forensic science laboratory uses a barcode system as part of its evidence
identification, the barcode would be affixed to the evidence when:
a. The evidence is about to be analyzed
b. When the final report is written
c. As soon as the evidence is accepted by the lab
d. When the evidence is put in central storage
e. When the evidence is returned to the submitting officer
7. Which of the following is not a forensic application of science?
a. Identification of human remains through dental x-rays
b. Verifying the composition of an aspirin tablet before it leaves the factory
c. Identification of a bag of tablets taken from a car when the driver is
stopped for erratic driving
d. Determination of why a Ferris wheel crashed at an amusement park when
three people were killed
8. From the time you graduate from high school until you are certified as a
forensic pathologist takes about    years.
a. 4
b. 8
c. 12
d. 13
e. 16

Introduction to Forensic Science 27

9. Go to the American Academy of Forensic Sciences (www.aafs.org) and look
up “Daubert Tracker.” This service permits a site visitor to:

a. Track Dauberts

b. Keep the forensic scientist up to date on some legal aspects of scientific
evidence

c. Determine when the annual academy meeting is

d. Keep track of new types of scientific evidence

e. Tracks dues payments to the academy
On the website for the Society of Forensic Toxicology (www.soft-tox.org), the
definition of forensic toxicology includes all of the following except:

a. Postmortem forensic toxicology

b. Analysis of suspected drug powders

c. Forensic urine testing

d. Analysis of blood and body fluids for human performance-altering drugs

e. All of the above are included in the definition of forensic toxicology

Matching
Determines cause and manner of death    
Identifies people from their teeth    
Reconstructs hard disc drives    
Analyzes bone fragments    
Determines competency to stand trial    
Determines how a bridge collapsed    

a. Anthropology
b. Pathology
c. Entomology
d. Computer forensics
e. Engineer
f. Odontologist

Fill in the Blanks
The             is the United Kingdom national forensic science
system.
Mail fraud is investigated by the            .
The federal laboratory whose responsibility is the investigation and analysis
of illicit drugs is the            

The two major duties of a forensic scientist in a crime lab  are

            and            .
The national “umbrella” organization for forensic science in the U.S. is
the            .
When evidence is brought into a crime laboratory it is delivered to
the             section.

Short Essay
What makes a science “forensic”? Give an example of dentistry (odontology)
that is forensic and one that is not. Do the same thing for engineering.
An increasing trend in crime scene investigation is to have forensic scientists
from a crime lab go to some crime scenes and help the crime scene investigators search for evidence. What are the advantages and disadvantages of this
practice?
Since , the national forensic science system in the United Kingdom now
operates on a fee-per-service basis. Everyone, police and defendants alike, is
charged for forensic analysis, whereas in the U.S., crime labs are generally
units of government for the use of police and prosecutors only. Defendants

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Forensic Science: The Basics, Second Edition

have no access to public crime lab facilities. What are the advantages and
disadvantages of each system? Why do you think that the U.K. changed to
the fee-for-service model?

Further Reading
James, S. H. and J. J. Nordby, eds. Forensic Science: An Introduction to Scientific and
Investigative Techniques. Boca Raton, FL: CRC Press,
Saferstein, R. Criminalistics: An Introduction to Forensic Science. 8th ed. Englewood Cliffs,
NJ: Prentice Hall,
Siegel, J., ed. Encyclopedia of Forensic Sciences. Vols. 1–3. London: Academic Press,
Thorwald, J. The Century of the Detective. New York: Harcourt, Brace & World,

On the Web
Take an online tour of a real crime lab. www.ok.gov/osbi/Forensic_Laboratory/Virtual_Tour/
index.html
Learn all about forensic entomology, including some real cases. http://research.missouri.edu/
entomology
You can learn a lot about forensic science and solve a virtual crime at www.virtualmuseum.
ca/Exhibitions/Myst/en/game/entry/index.phtml
How does a forensic anthropologist analyze bone fragments? www.anthro4n6.net/forensics

2

Crime Scene Investigation

Learning Objectives








1. To be able to describe the characteristics of a crime scene
2. To be able to list the steps in the investigation of a crime scene
3. To be able to list the steps in the collection of evidence
4. To be able to define chain of custody and describe its elements
5. To be able to list and describe the ways of searching a crime scene
6. To be able to list and describe the ways of documenting a crime scene
7. To be able to complete a rough draft and final sketch of a mock crime scene

29

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Forensic Science: The Basics, Second Edition

Chapter 2

Crime Scene Investigation
Chapter Outline
Mini Glossary
Introduction
The Crime Scene as Recent History
Crime Scene Investigation Process
A Crime Occurs and Is Discovered
The First Officer at the Crime Scene
Protocol at the Crime Scene
The Preliminary Scene Examination
Systematic Search of the Crime Scene
Recording the Crime Scene
Collection of Evidence
Reconstruction
Summary
Test Yourself
Mini Lab Activities
Further Reading
On the Web

Mini Glossary
Authentication:  Documenting who has possession of crime-related evidence from
the point of collection to its appearance in a court of law.
Chain of custody: A physical log for a single piece of evidence that documents
who had possession of the evidence and when the evidence was in his or her
possession. It is a flow chart of the movement of evidence from collection to
processing at the crime lab to presentation in court.
Corpus delicti:  The Latin translation is “body of crime.” Corpus delicti means that
it must be proven that a crime has occurred before an individual can be convicted of committing a crime. For example: A death must be ruled a homicide
before anyone can be tried for murder or a fire must be ruled as an arson in
order for a person to be tried for setting the fire.
CSI:  The acronym for Crime Scene Investigation or Crime Scene Investigator.
Documentation:  Recording in detail the conditions when the crime occurred.
Druggist’s fold (or evidence fold): Small pieces of evidence are packaged in
druggist folds (papers) to ensure that they are not lost. They are sometimes
also referred to as “evidence folds.” The folded paper is then placed in standard evidence packaging.
Exemplars:  These are baseline, known evidence such as fingerprints, DNA, hair,
or voiceprints collected from suspects or victims in order to compare with
evidence taken from a crime scene. Exemplars are sometimes referred to as
“knowns” or “controls.”

Crime Scene Investigation 31

First responder:  The initial police officer at the crime scene is regarded as the
first responder.
Modus Operandi (MO):  The Latin translation means “mode of operation.” This
refers to the style or method that a criminal uses when committing a crime.
For repeat offenders, an MO may assist investigators in locating the suspect
due to his or her characteristic way of committing the crime.
Postmortem Interval (PMI):  Postmortem interval is the length of time from discovery of a dead body to the time the victim died.
Probative:  A piece of evidence that tends to prove or disprove a fact or assertion.
Protocol: In criminal investigations protocol is an established, detailed plan or
procedure that must be implemented for evidence to be valid.
Search methods:  Evidence may be located using a systematic approach to survey
the site. These methods employ spiral, grid, line, or zone techniques.
Sting operation: Law enforcement agents stage a scenario whereby criminals
are encouraged to commit crimes that they would probably have committed
anyway.
Tamper-evident packaging:  Specific types of containers or packages for crime
scene evidence that have seals that can only be opened by tearing or cutting,
thereby giving proof of access.

Introduction
A crime has been committed. It was a recent event, but it happened in the past,
therefore a crime scene can be thought of as a piece of history. Like all historical places, the crime scene has a story to tell. Anthropologists and archaeologists
investigate places where ancient civilizations once lived. They look for evidence of
who lived there and how they lived. Perhaps they will find clues as to the fate of the
citizens. Historians examine the site of a Civil War battlefield to learn many things,
like how the battle was fought, how many people fought and died, what they wore,
and what armaments they used. Crime scene investigators carefully and systematically sift through a crime scene to learn how and when the crime was committed,
who committed it and why, and perhaps what items may have been removed from
the scene. All of these historical scenes—the ancient village, the hundred-year-old
battlefield, and yesterday’s homicide scene—contain evidence that, if properly collected, analyzed, and interpreted, tells the story behind the events that took place.

The Crime Scene as Recent History
It is useful to think of a crime scene as history because it has much in common with
older historical sites. The proper methods of conducting an archaeological dig and
reconstruction of a battle are similar to the methods that should be used to successfully search a crime scene. Some areas of similarity are as follows.
• Timing. A historical scene changes all the time, especially if it is outdoors.
For ancient ruins, this may not be too important in the short run. A couple
of weeks of delay in searching a ten-thousand-year-old village will probably
have little consequence. For crimes that occurred only a few hours or days

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ago, however, time may be of the essence. For example, if a burglary isn’t discovered and solved within an hour after it occurs, it never will be. The trail
gets cold really quickly.
• Plan of attack. There must be a plan for systematically searching the site
that ensures that no stone is left unturned without needlessly covering the
same area again and again.
• Safety issues. Safety of the scene searchers must be considered. Hazards at
the ancient remains of a city are going to be different from those at a modern
crime scene, although the flooring in a house that had major fire damage
may be just as unstable as the ancient ruins of a building.
• Appropriate personnel. Only highly qualified, trained personnel should
conduct the search of the site.
• Controlling the scene. Contamination must be minimized by permitting
access to the site to as few people as possible. Additionally, those persons at
the scene may be asked to give elimination samples if necessary to compare
with collected evidence. For example, CSI team members may be asked for
samples of their DNA.
• Documentation. Every instance of searching an historical site further
changes it. Evidence is found and then is moved or removed. Gathering evidence is a vital part of learning the story of the site. Once it changes, it will
never be the same again. This is an important concept in searching a crime
scene. The crime scene must be documented thoroughly so that a record can
be made of its condition when the crime occurred. This includes labeling the
location of each piece of evidence when it is discovered. Ultimately, the evidence will be useful in establishing that a crime has actually occurred and
someone must be prosecuted for it, a process called corpus delicti.
One major difference in the documentation of a crime scene from that of historical
sites is that there must be a chain of custody for each piece of evidence that is removed
from the scene. The chain of custody begins when the evidence is discovered.
In the remainder of this chapter, the crime scene investigation process will be
detailed. Evidence collection procedures described are recognizing evidence, documentation of evidence, collection of evidence, and the delivery of evidence to the
laboratory for analysis.

Crime Scene Investigation Process
A number of procedures take place at a crime scene. Some procedures are always
followed, while others depend on the nature of the scene and the circumstances surrounding the crime. Figure  shows the overall process that takes place during a
crime scene investigation.

A Crime Occurs and Is Discovered
There are three ways that crimes are discovered.
1. A witness sees a crime in progress and reports it to the police.
2. A victim of a crime reports it to the police.
3. The police discover a crime in progress.

Crime Scene Investigation 33

Hot
Search

Victim

Witness

A Crime Is
Discovered

First Responder

Seals Off Scene
Tends to Injured
Maintains Safety

Police

Crime Scene
Investigation
Team Arrives

Preliminary
Scan of Scene

Chain of
Custody

Crime and
Crime Scene
Reconstruction

Evidence
Collected

Scene
Sketched and
Photographed

Systematic
Search to
ID Evidence

Figure   This diagram shows the steps in a typical crime scene investigation.

In the first case, someone witnesses a crime in progress. An example of this is
when someone is walking down the street at night and sees someone leaving a dark
electronics store with arms full of merchandize. Another example is when someone
hears what sounds like a gunshot at a next door neighbor’s house and runs over to
investigate, only to find the owner dead. No one else seems to be around.
In an example of a crime being reported by a victim, the owner of a small business arrives at work one morning and finds that the safe has been opened and
money stolen. The owner calls the police to report the robbery and the crime scene
investigation begins.
A situation where a police officer discovers a crime in progress is when an officer
stops a speeding car and finds a hoard of illegal weapons in the back seat. Police
may also “discover” a crime by staging a sting operation. These are situations
where law enforcement agents set up a scenario whereby criminals are encouraged
to commit crimes that they would probably have done anyway.
Example of a Sting Operation
A sting operation is set up by local police and/or federal agents as a type of
proactive law enforcement. One of the earliest examples of a sting occurred
in Washington, D.C. in the s. This was a joint FBI and Washington, D.C.
Police Department operation to combat major theft rings operating in the city.
The agents and police set up a storefront operation and put the word out on
the street that the store was a well-financed “fencing” operation (a fence is
someone who buys stolen merchandise and resells it at a profit). Further, the
word was that this operation was being run by “organized crime” (the Mafia).
Anyone who had something of value to sell would get top dollar with no questions asked.

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The “store” was rigged with a one-way mirror so that the police could videotape
the “sales” through the glass without being detected. All the crooks could see was
a mirror. To make sure that each seller would look at the camera, a picture of a
bikini-clad model was prominently posted.
The sting operation was supposed to last a month and had a budget of several thousand dollars. It was so wildly successful that the operation ran out of
money in a week and had captured more than two hundred transactions on tape.
Included in the haul were stacks of stolen Social Security checks and typewriters
(no computers back then) from government buildings.
So as to avoid having to track down all of the crooks and arrest them, the
“owners” advertised a big party at the end of the operation. Virtually all of the
participants were invited and were promised a chance to meet the “Godfather.”
What they got were handcuffs and a trip to jail. Faced with a videotape of their
“transactions” every one of the scofflaws pled guilty to theft.

The First Officer at the Crime Scene
Archaeological digs and battlefield reconstructions involve large teams of searchers
from the very start. In a crime scene search, however, the discovery of the crime
usually results in a police officer being dispatched to the scene. This officer has several important duties:
1.
Ascertain whether the perpetrator is still at the scene. If so, a hot
search for the perpetrator should commence immediately. If this proves futile,
later on, detectives or criminal investigators will likely perform a cold search,
whereby people in the neighborhood are interviewed to determine whether
they saw the crime being committed or saw the perpetrator flee the scene or
observed other suspicious events.
2.
Tend to the injured. If an ambulance is needed, it should be called right
away. Waiting can cost lives.
3.
Notify supervisors, medical examiner, crime scene team, or other
personnel. It will take time for requested personnel to arrive at the location. Once the team has arrived, the investigation process can commence.
4.
Secure consent or a warrant to search the scene. Unless there is an
emergency situation, such as threats to someone’s life or safety, destruction
or removal of evidence, or possible escape of the perpetrator, the officer should
obtain the right to enter a crime scene. According to the Fourth Amendment
of the United States Constitution, in order for the crime scene search to be
constitutional, consent must be given voluntarily by a person reasonably
believed by law enforcement officers to have lawful access and control over
the premises. In most cases, this will be the person who called police to the
scene. If consent is not possible, a warrant or judicial order authorizing a
search must be obtained.
5.
Secure the scene. Contamination of the scene must be minimized. The
number of people who have access to the scene must be limited and the entry
and exit paths of these personnel should be determined. Initially it is advantageous to make the scene perimeter large to prevent loss of any pertinent
evidence. For example, if a crime occurred in a home, consider the entry and
exit of the perpetrator as important and secure the outside of the home, too.
Footprints and tire tracks are just as important as the physical evidence

Crime Scene Investigation 35

found inside a residence. If a body is found in the woods, the potential scene
can be quite large and isolating it can be difficult.
6.
Avoid walking through the scene and searching for evidence.
Remember that any contact with a crime scene alters it forever. Searches
of even localized crime scenes must be done by professionals who have formulated a search plan. In some cases, what appears to be the scene of the
crime may not be. The site may have been set up to look like a crime scene
so as to divert attention from the real scene.
7.
Note any obvious safety hazards. Strange smells could be gas or potentially dangerous chemicals that may pose a fire or poison hazard. Structures
may be weakened or rigged to kill or maim. Electrical wires may be exposed.
The job of the first officer at the scene is not to remediate these hazards
but to protect others from them and to warn personnel who subsequently
come to the scene. The Universal Studios movie, Backdraft had a scene
that illustrates the situation where a crime scene is rigged to cause harm to
investigators. A fire was set in a building that was then completely sealed up.
When the oxygen became depleted and could no longer support flames, the
fire began to smolder. When the fire department arrived and broke in to the
building, the onrush of oxygen into the building caused the fire to explode
into flame. Firemen were killed and injured. This also happens in real life
fires and may occur naturally as a fire proceeds.

Protocol at the Crime Scene
The examination of a crime scene must follow protocol established for the crime
scene investigative unit. Protocol is a detailed plan or procedure established by law
enforcement that must be implemented for evidence to be valid and admissible in a
court of law. Following protocol insures that all crime scenes will be investigated in
the same manner by using established guidelines. Following procedural guidelines
becomes important when police officers and crime scene investigators must testify
in court regarding the validity of evidence.
As soon as possible after the crime scene has been discovered and protected, the
crime scene investigation (CSI) unit will arrive. If there is a dead body at the
scene, someone from the medical examiner’s or coroner’s office will take charge of
processing the body. This person will normally be a forensic pathologist who certifies
that the person is dead and makes a preliminary determination of the postmortem
interval (PMI), or the time since death. This topic will be covered in more detail
in the chapter on forensic pathology. If there is a body at the scene, some police
departments dispatch a death scene CSI squad to process and remove the body from
the scene. This processing includes photographing the body, making sure all trace
evidence is protected and gathered, and transporting the body to the medical examiner’s or coroner’s laboratory.
The crime scene unit, which is usually made up of specially trained police officers, takes charge of the crime scene. Each member of the team has a defined role,
such as sketcher, photographer, searcher, or documenter. Fingerprint and blood
spatter technicians will also be called to the scene if needed.
The Preliminary Scene Examination
The first duty of the CSI unit is to conduct a preliminary examination of the scene.
This is done for a number of reasons. Safety hazards will be promptly addressed

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Forensic Science: The Basics, Second Edition

and remediated. The boundaries of the crime scene must be ascertained. This may
be a simple process if the crime clearly occurred in one room of a house (keeping in
mind that routes of entry and escape can be very important sources of evidence). If
the crime is outdoors, then fixing the boundaries of the scene can be very difficult.
The area where the crime was committed may only be the primary crime scene.
Perpetrators often carry evidence away from the scene and there may be one or
more secondary locations where important evidence may be found.
Additionally, if preliminary examination of the scene has some aspects similar to
other recent crimes in an area, the investigators may look at the modus operandi
or MO of the crime. Modus operandi is the pattern or method of operation that a
criminal repeatedly uses during an illegal act. A repetitive MO could imply the work
of a single criminal in more than one crime.
Systematic Search of the Crime Scene
After the preliminary examination of the scene has been made, systematic documentation and searching begin. This process is carried out in ways that minimize
alteration of the scene. It is easily and permanently altered as people conduct their
investigations. Photographing the scene is carried out as early as possible. Although
regular photography is still widely used in crime scene investigations, the recent trend
has been to use digital photography because photographs can be seen immediately.
In addition, digital pictures are easily incorporated into computerized crime records
and reports. It is also common for the crime scene team to use videotape to complete a
walk-through of the scene. This is very effective for the jury in order to get an overall
sense of the scene. It is important, though, for the audio of the tape to be silenced so
that no comments are inadvertently shared that might influence the jury.
One of the first decisions to be made is the search pattern that will be used at
the crime scene. There are four basic types of search methods that can be used,
depending on the type of crime scene. For example, if the entire crime scene is one
room in a house, a search may begin at one end of the room and proceed in a spiral
fashion toward the center or may be a back-and-forth (line) pattern across the room.
If the scene includes several rooms, each one is searched systematically using a zone
method. If the scene is outdoors in a large area, it may be necessary to divide the
scene into grids and then search each grid. Examples of each method are shown in
Figure 
Sometimes unusual tactics are used to search a crime scene such as those
described in the shooting of police officer Yvonne Fletcher at the Libyan
Embassy in London, England. It is seldom necessary to devote the large amounts of
investigative resources that were used in this case, but the crime was very serious
and had major political implications at the time. Also, the police had lost one of their
own and they were eager to find the evidence that would bring the killer(s) to justice. This case illustrates that sometimes unusual methods are needed to effectively
search a crime scene.
Yvonne Fletcher
On April 27, , an eleven-day siege ended at the Libyan Embassy in London. The
siege was the result of the shooting of a London police officer, Yvonne Fletcher, on
April Witnesses saw smoke and flame from a first floor window of the Embassy
right before the officer fell. When she was loaded onto a gurney and taken to the
hospital, a slug that had hit her fell out of her body and onto the ground. The

Crime Scene Investigation 37
Crime Scene Search Methods
Grid Method

Line Search

End
Start

Zone Method

Spiral Method

Figure   Four general methods used to systematically search a crime scene.

slug was missing when the forensic pathologist did the postmortem examination.
It was very important to find the slug so it could be compared to the weapon if
found. The area in question was a large courtyard in front of the embassy. More
than fifty police officers gathered in the courtyard and then crawled shoulder to
shoulder on their hands and knees all the way across the courtyard in search of
the slug. It was found and later matched to the suspect weapon.

Something for You to Do
Go into the largest room in your house (this may be the garage). Ask someone in your family to plant a piece of “evidence”
in the room. This could be a small object that could be evidence in a real crime. It could be hair, fiber, or paint chips, or
other trace evidence. You should figure out how you would search this scene to make sure you cover the entire scene. You
also want to make sure you don’t go over the same ground more than once so as to minimize contact and contamination of
the scene. Draw a diagram of the search pattern you would use to search this scene.
Now go into the smallest room in your house and repeat this exercise. Next go outdoors to your front yard or back yard
or a nearby park and repeat the exercise again. Did you decide to use the same type of search pattern in each case? Why?
In which case(s) would you try and get help in searching the scene? After you have developed a strategy for searching each
scene, pick one and try to find the object.
See if your strategy works. You may not be able to find the object, especially if you don’t know what you are looking for
or you may inadvertently step on it or track extraneous material into the scene and mistake this for evidence. This is what
crime scene investigators face every day in their work. Crime scene investigation is a difficult process even for experienced
investigators.

Recording the Crime Scene
Historically, there have been two basic methods of documenting a crime scene and
recording its condition and the locations of all of the evidence. The first was making

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Forensic Science: The Basics, Second Edition

Figure  A shoe print in soil with a ruler. The ruler is used to show the size of the shoeprint.
With permission of Bodziak, WT. Footwear Impression Evidence, 2d ed., New York: Taylor & Francis,


a sketch of the crime scene, while the second was using photography to document a
scene. Each method enhanced the effectiveness of the other.
The crime scene sketch was done by first making a freehand sketch and then taking measurements of the positions of various objects with reference to at least two fixed
positions in the scene. Later on, this sketch would be translated into a scale drawing
of the scene. The second method was by still photography (35 mm) using regular film.
Many pictures would be taken under various light conditions and at various distances
and angles in the hope that some would properly record the scene. Measuring instruments, such as small rulers, would be put in photographs where size perspective was
important, as with shoeprints and tire treads. Without a scale to show size for such
evidence, it would be difficult to admit such evidence into court as demonstrative evidence. Figure  shows a picture of a shoeprint. Note the ruler in the picture.
Today, the situation is different but some of the old practices are still used. Handdrawn crime scene sketches, as shown in Figure , are still used and measurements taken, but the scale drawings are often rendered on a computer that has
specialized crime scene reconstruction software.
Sometimes scale models of crime scenes are made from cardboard, wood, plaster,
and the like. An extreme example of modeling is performed at the Federal Bureau
of Alcohol, Tobacco, and Firearms (BATF) at its fire research laboratory near
Beltsville, MD. In cases where a fire has occurred in an apartment or house, a construction crew builds an exact model of the structure to scale and then re-creates
the fire conditions as precisely as possible so the progress and damage caused by the
fire can be studied. The BATF laboratory employs professional builders to construct
the structures that are then sacrificed to research. The fires are carried out in a
huge building equipped with exhaust fans and filters that prevent particulates and
harmful gases from escaping.
Today, crime scenes are often videotaped. A crime scene investigator will walk
the crime scene with a video camera and take footage from all angles. This can
take the place of some of the still photography, but will not replace the crime scene
sketch. There is even one company, 3rd Tech, that makes an automatic video system. A camera is set up in a room and it takes thousands of frames of the scene in a
degree arc that, when reconstructed, provides unprecedented details about the
locations of objects and perspectives at the scene.

Crime Scene Investigation 39

Scale: ¼ inch = 1 foot

(a)

 (b)

Figure   Rough draft (a) and (b) final sketches of a crime scene. From: www.cool physics.org /Crime%20Sc ene%20
05% 20v2.ppt

The 35 mm cameras are still used at crime scenes to photograph individual
objects, but this method of taking photos is rapidly being replaced by digital photography. Advantages to digital photography of crime scenes include the ability to
easily incorporate pictures into reports and the ability to examine a photo right
after it has been taken so the photographer will know right away if the picture is
useable. Digital photographs can also be enhanced or touched up using computer
software such as Adobe Photoshop ®. This is not the same as altering digital photos, which would be called into question in a court of law. The forensic photographer must inform the court which photos were enhanced and what was done to
enhance them. Enhancement is used only to make the original photo clearer for
presentation to the jury, and must never be used to change the photographic evidence or alter it.
Photographs are taken in an organized manner. First the entire scene is photographed from each corner of the structure, room or object. Then the item of interest
is photographed from a distance, mid-range, and then close up with and without
a scale in the picture. Figure  shows outside and interior room photography.
Figure  illustrates photography of a victim.
Additionally, it is useful to photograph any bystanders at the crime scene. These
photographs can aid in identifying witnesses or in some cases the actual perpetrator, as criminals sometimes like to watch the police process crime scenes.
Collection of Evidence
There is an old saying at crime labs: “You cannot make chicken salad out of chicken
feathers.” This is a reminder that the results of the scientific analysis of evidence

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Forensic Science: The Basics, Second Edition

Distance shot of residence, walkway to entrance, front door entrance

Living room
views from all
four corners.

Figure   Crime scene photography. Outside photographs should document the entire residence,
the path to the residence and the entrance. Similar shots should be made of the rear of the home.
Each room should be photographed entirely and as seen from all four corners.

A

B

E
C

F

D

G

H

I

Figure  Crime scene photography. The female victim is photographed at various locations in
the room (A–E). Then close-up shots are captured of her injuries and potentially important evidence
(F–I).

Crime Scene Investigation 41

Precise
Documentation
of Location

Remember to
Collect Knowns

Tamper Evident
Packaging

Recognition

Collection

Package
Preserve

Must Consider
Context of Crime

Collect as Much
as Possible

Chain of Custody

Figure   The steps in the evidence collection process.

from a crime scene are only as good as the evidence brought to the lab. If evidence
is contaminated or degraded or the wrong evidence is collected, the evidence will
be of limited or no value. The collection, preservation, and packaging of evidence
are crucial to a successful criminal investigation. Under ideal circumstances, crime
scene investigation would be done by the forensic scientists who analyze the evidence because they know best how to recognize, collect, preserve, and package it.
Unfortunately, caseloads being what they are, forensic scientists cannot afford the
time it would take to process all crime scenes. The trend today, however, is to have a
forensic scientist team respond to homicides and other serious crimes and they work
with the crime scene investigators to process the scene. A group of forensic scientists
usually volunteer for crime scene duty. They form a team of experts whose areas of
expertise might be important to the investigation. This would include DNA analysts,
serologists (who are experts in locating and collecting small blood stains or other body
fluids and who can process blood spatter patterns), and trace evidence scientists (who
are adept at recognizing which trace evidence is important and how to properly collect it). Other specialists may be called in from time to time. For example, one or more
forensic drug chemists are usually called on to help investigate scenes of clandestine
drug activity such as a methamphetamine lab operation. These scenes can be very
dangerous because of flammable chemicals and a lack of safety concerns. Clandestine
laboratories are discussed in greater detail in the chapter on illicit drugs. When forensic scientist crime scene teams are sent to help local crime scene investigators process
complex scenes, there is an agreement in place that establishes when the lab team is
sent out and how the chain of command at the crime scene will be determined.
Three major steps in the process of evidence collection are recognition, collection,
and packaging/preservation. Each has other considerations that are important for
the other steps. Figure  shows how these steps and their associated processes are
related.
Recognition of Evidence
An object at a crime scene must be recognized as evidence before it can be collected. When you did the exercise of searching a room in your house or outdoors
for evidence, you had the advantage of knowing what is supposed to be in these
rooms. It is easier to recognize something that is out of place or doesn’t belong. That
advantage is lost at a crime scene. The crime scene investigators do not know what
objects belong to that particular location and therefore they don’t know what objects

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Forensic Science: The Basics, Second Edition

may have been left there by the perpetrator. So how do investigators know what is
evidence and what is not? This takes a thorough knowledge of what is likely to be
present at the scene of a given type of crime. Homicides, burglaries, sexual assaults,
and other types of crimes usually contain characteristic types of evidence that the
crime scene investigator would hope or expect to find. For a homicide, this might
be a weapon, blood, fiber, and hair, and fingerprints. For a burglary, one might
expect to find tools, glass, soil, and perhaps fingerprints. For a rape scene, investigation often turns up hair, fiber, and body fluid such as semen. This doesn’t mean, of
course, that these are the only items that will be present. These are guidelines that
investigators use to start their search. The context of the crime, the type of crime,
and the type of scene are very important in providing clues to what evidence should
be present. If the crime looks similar to another recent one, investigators might be
watchful for evidence that would suggest the same MO (modus operandi) and therefore the same perpetrator.
In general, there is no such thing as too much evidence. If an investigator has
doubts about whether an object is significant, it should be collected and sent to the
lab. As the investigation proceeds and the scene is reconstructed, it will be easier
to determine whether the material is actually evidence. Once the crime scene unit
is finished with the scene and it is released to the owners, it will not be possible to
come back and collect more evidence. For example, suppose an investigator comes
upon fibers at a scene and neglects to collect them. Later on, it is determined that
these fibers are important evidence, but the owners have taken possession of the
premises and have vacuumed the carpets. The evidence is lost forever.
Once evidence is located but before it is collected, its exact location must be
recorded. This may be done by photography and/or measurements with respect to
a fixed object. This is necessary so that when reconstruction of the crime scene is
done, the location of the evidence will be known. After it is moved and taken to the
lab, evidence cannot be relocated at the scene. Besides the location of the evidence,
other information must be recorded for chain of custody purposes. This will be discussed in more detail below.
Collection
How much evidence should be collected? The short answer is: as much as possible.
At clandestine drug laboratories, everything that could have any remote connection
with the manufacturing operation is collected. In the case of illicit drug seizures,
all of the drugs are collected, even if tons are involved. The forensic science laboratory will sort out the issue of sampling for analysis purposes later. In many cases
involving trace evidence, the lack of sample may limit the tests that the scientists
can do. In addition, the rules of evidence in the United States require that the defendant be given a fair chance to perform tests on the evidence. If it can be shown that
there was more evidence available that wasn’t collected or the government crime lab
used all that was collected, the defense attorney may be able to have the evidence
excluded from the trial on the grounds that the defense didn’t have an opportunity
to analyze the evidence with its own expert.
Another important consideration in the collection of evidence is the issue of comparison samples, or “knowns.” Knowns are also referred to as exemplars. Exemplars
are baseline, known evidence such as fingerprints, DNA, hair, or voiceprints collected from suspects or victims for comparison with evidence taken from a crime
scene. (The concept of known versus unknown evidence is further discussed in the
next chapter.) With many types of evidence, the probative value or significance in
the case can be greatly enhanced if it can be compared with and linked to a known

Crime Scene Investigation 43

material or object. Fingerprints found on an object have little meaning unless they
can be compared to the exemplar fingerprints of a suspect and then shown to have
originated from that person. Known evidence may be found at the crime scene or
may be taken later from a suspect or another location linked to the primary crime
scene. Known evidence (or exemplars) may either link a suspect to the crime or may
serve as elimination samples—samples that clear an individual from involvement
in the crime.
A Really Big Case
In , the U.S. Coast Guard seized a private boat that was racing up the
Atlantic Coast near Virginia. The boat was boarded and tons (17, pounds)
of suspected marijuana was found. This was taken to the Drug Enforcement
Administration (DEA) lab in Washington, D.C., where it was identified as marijuana. Then it was transported to the Baltimore garbage incinerator where it
was to be destroyed. The defense attorney in the case wanted the evidence analyzed by his own expert prior to its destruction. The expert (one of the authors of
this book) went to the incinerator and found hundreds of bales of marijuana, each
weighing hundreds of pounds. He took representative core samples from each
bale. A DEA chemist followed behind and also took a sample from each bale. After
each bale was sampled, it was incinerated. The resulting total sample weighed
approximately 5 pounds. This raises the issue of representative sampling of large
exhibits of drugs. This topic is covered in the chapter on illicit drugs.

Packaging and Preserving Evidence
Once the evidence has been located and collected, it must be properly packaged. This
may not seem too important at first glance, but it can be critical to a case. There are
physical, scientific, and legal requirements that determine how evidence should be
packaged, and today appropriate packaging is available for all types of evidence.
Attention to detail and following proper protocol are vital when collecting evidence. Only one type of item can be collected per container or package. Crime scene
personnel must change their gloves and tools after each item is collected to avoid
contamination. These procedural guidelines make collection and preservation a long,
tedious process, but they are essential for the proper preservation of evidence.
The chain of custody. Rules of evidence in federal and every state court in
the United States require that all evidence be authenticated. Authentication
requires:
1. A record of who is in possession of the evidence from the time it is collected at
the crime scene until the time it is delivered to court. This detailed record is
called the chain of custody.
2. The evidence must also be uniquely identified (for example, using a bar code)
in such a way so that it cannot be confused with any other piece of evidence
and so that it can be shown that the evidence being used in court is the same
evidence that was taken from the crime scene.
3. The evidence must also be packaged in tamper-evident packaging. This is
both a document and a process that insures the integrity of the evidence. If the
chain of custody has a substantial break—one that would seriously call into
question the quality or integrity of the evidence—the evidence may be ruled
inadmissible in court.

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Forensic Science: The Basics, Second Edition

Tamper
Evident
Packaging

Chain of
Custody
Begins

Evidence
Collected

Police
Dept.
Property
Room

Criminal
Investigator

Evidence
Intake at
Crime Lab

Evidence
Intake at
Crime Lab

Evidence
Storage
at Lab

Scientists
at Lab

Evidence
Storage
at Lab

Criminal
Investigator

Police
Dept.
Property
Room

Criminal
Investigator

Court

Figure   The flow of evidence from crime scene to court.

At one time, certain evidence from sexual assault cases was frequently challenged on chain of custody grounds. In cases of sexual assault, the victim is taken
to a hospital (or often now to a SANE clinic—sexual assault nurse examiner). The
victim’s clothing is removed pursuant to an examination by a nurse or doctor. In
years past, the clothes might be left in an examining room or elsewhere in the clinic
that was not secure from the public. This clothing could potentially be the source of
critical evidence of the identity of the perpetrator, especially in these days of DNA
typing. Since no one was in possession and in charge of the evidence, the chain of
custody might have been seriously damaged and evidence from these clothes might
not have been admissible. Today, most hospitals and clinics have doctors and nurses
who are trained in the collection and preservation of evidence from the victim. Crime
labs or SANE clinics now supply doctors and nurses with “rape kits”—evidence kits
that contain packaging for various types of evidence such as hair, vaginal swabs,
individual articles of clothing, and so on. The packaging is suitable for the criminal
justice system and the chain of custody.
Figure  shows a typical journey of evidence from crime scene to court with
chain of custody considerations along the way. Note how many times the evidence
changes hands during its journey. This is why it is so important to maintain a
record of who is in possession of the evidence at any given time.
Two of the most important elements of the chain of custody are tamper-evident
packaging and the custody form. Tamper-evident packaging is just that. Once the
package is sealed, no one can open it without leaving evidence that the package was
opened. It must be cut or torn to get inside. This is sometimes erroneously called
“tamper-proof” packaging, but there is no such thing. Any package can be opened
using whatever force is necessary. In addition, there must be a form, sometimes
incorporated in the package itself that has space for whoever has custody of the evidence to sign and date the form. Every time the evidence changes hands, the donor
and receiver sign and date the form. This form is kept with the evidence at all times.
Figure  is an example of a chain of custody form.

Crime Scene Investigation 45

Figure   Tamper-evident packaging.

An alternative to the tamper-evident container is tamper-evident tape. This can
be applied to any bag, box, or pouch. It is very sticky and shreds when removed.
Also, some of the glue from the tape is left behind on the package. Figure  shows
one type of evidence tape.
Preserving Evidence
In addition to being tamper-evident, packaging for evidence must also be designed
to preserve the evidence to the maximum extent possible. From the time evidence is
collected, it may be weeks or months until scientists at the crime lab are able to analyze it (many labs have several months of case backlogs). Different types of evidence

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Forensic Science: The Basics, Second Edition

Figure   Tamper-proof evidence tape.

require unique packaging to preserve it. Some of the more common evidence types
that need special packaging are listed below.
• Living plants (marijuana) must be packaged in “breathable” containers
such as paper bags. If the plants are packaged in airtight containers, they
will rot and may become useless.
• Biological evidence (wet blood or body fluids) should be allowed to dry or,
if packaged wet, the container must be breathable. Blood can also be packaged in a glass or plastic culture tube that contains a preservative, usually
ethylenediamene tetraacetic acid (EDTA).
• Wet paint should be allowed to dry or packaged in breathable container
• Trace evidence (hair, fiber, small paint chips, or glass) should be placed in
an envelope or plastic baggie sealed on all sides. It is not recommended to use
tape to hold this evidence (commonly called a “tape lift”). The glue in the tape
can interfere with the chemical analysis of the evidence and the evidence
may be difficult to remove from the tape. Evidence can be put in a druggist’s fold (also called evidence fold) and then put into a tamper-evident
envelope. A druggist fold or evidence fold is a piece of paper folded in such a
way to keep the evidence from leaking or falling out.
• Small amounts of powder should be put in paper with a druggist’s fold
and then an envelope or baggie.
• Fire residue must be put in an airtight container. Unused paint cans
are best. If fire residue is put in breathable containers, the accelerant will
evaporate.
As a side note, fingerprints are typically the last evidence taken at the scene due
to possible contamination of fingerprint dust with the other crime scene evidence.
Reconstruction
Remember that a crime scene is a slice of recent history. It has a story to tell and the
evidence at the scene helps tell the story. Each piece of evidence contributes to the
story. Once the evidence has been collected, analyzed, and compared to known evidence, the criminal investigators, often with the help of forensic scientists, attempt to
reconstruct the crime, including the identities of the victim(s) and the perpetrator(s)
and the sequence of events that took place leading to the crime. The focus here is, of

Crime Scene Investigation 47

course, to link the suspect(s) to the crime through the evidence and build a case that
will stand up in court and convince a judge or jury of the guilt of the suspect beyond
any reasonable doubt. Many types of evidence and circumstances go into building
such a case, but one of the major foci must be the place where the crime occurred
and the evidence that always accompanies the commission of any crime.

Summary
A crime scene is a place where a recent historical event—a crime—has taken place.
As such, it has a story to tell about the events leading up to the crime, the crime
itself and the immediate aftermath including the escape of the perpetrator from the
scene. Like scenes of ancient history, crime scenes contain clues or evidence that
help tell the story of the crime. This evidence must be recognized, carefully collected
and preserved and delivered to a crime laboratory for analysis.
The basic steps in crime scene investigation include:
• Discovery of the crime
• First officer responds
• Crime scene protocol
• Preliminary scene examination
• Systematic search
• Documentation
• Evidence collection and preservation
• Reconstructing the crime
This process must meet legal requirements, including the chain of custody, in
order for the evidence to be admissible in court.

Test Yourself
Multiple Choice
1. A crime scene does not have which of the following in common with historical events:

a. Highly trained persons should be involved in the investigation

b. A systematic plan must always be followed

c. The safety of the searchers is important

d. Care should be taken to avoid contamination

e. Documentation of items collected is optional
2. The purpose of documenting the chain of custody of evidence is

a. To make sure it gets to the correct scientist in the lab

b. To keep the evidence from falling out and getting lost

c. To make sure that the evidence is admissible in court

d. To keep it from getting stolen

e. To be able identify the type of evidence
3. Which of the following is not a duty of the first responder to a crime scene?

a. Tend to injured people

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Forensic Science: The Basics, Second Edition


b. Transport a dead body to the morgue

c. Seal off the crime scene

d. Notify crime scene investigators

e. Perform a hot search
4. Search methods of a scene include which of the following:

a. Grid, line, zone, and aerial

b. Grid, line, zone, and spiral

c. Line, zone, aerial and spiral

d. Zone, spiral, sweep, and line

e. Aerial, sweep, line and zone
5. Photographs of a crime scene should be taken

a. From a distance, mid-range and close-up with and without a scale

b. From a distance, mid-range and close-up with a scale

c. From a distance and close up with and without a scale

d. From four views at a distance and close up

e. Only from mid-range and close up

True or False
6. All crime scene searches can be done by the grid method.
7. A cold search takes place long after the crime has occurred and assumes
that the perpetrator has left the area.
8. An emergency medical technician (EMT) goes to a death scene to certify the
death and make preliminary determinations as to the PMI.
9. A situation in which a police department sets up a scenario where people can
commit crimes if they choose is called a reconstruction.
A druggist fold is used to package trace evidence.
Hand drawn sketches of crime scenes are no longer done because of computer
crime scene software.
All crime scenes are searched using the same type of search pattern

Short Essay
List at least three roles that crime scene investigators can play at a crime
scene.
Research and describe the difference between a primary crime scene and a
secondary crime scene?
List three types of evidence that should be placed in “breathable” containers
and explain why it is important to use these types of containers.

Matching
Chain of custody
Corpus delicti
Exemplar
First responder
Modus operandi

a. The police officer who responded to a call
b. The methods of a suspect when committing a crime
c. The length of time from death to discovery of a body
d. A staged event to cause a suspect to commit a crime
e. The log of evidence from crime scene to court

Crime Scene Investigation 49

PMI
Probative
Protocol
Sting operation
Tamper-evident
packaging

f. Evidence used for comparison, a known sample
g. Containers for evidence that seal and prevent altering
h. Evidence that can prove or disprove
i. Deems it necessary to prove a crime occurred
j. Detailed plan or procedure followed in an investigation

Mini Laboratory Activities
MINI LAB 1: MAKING A DRUGGIST (EVIDENCE) FOLD
1. Take an 8½ × 11 sheet of paper and fold the upper right edge across the paper
until it meets the left edge. The result will be a triangle with an extra edge on
the bottom that is untouched.



1a

2. Cut off the unfolded edge so that when the triangle is opened the remaining
paper will be a square.



1b

3. Re-fold the paper back into a triangle with the base at the bottom and the
points at the top and sides. Fold in the sides of the triangle so that you have 3
approximately equal parts as shown below.


4. The pointed top of the evidence fold can now be opened
1c and serves as a pouch
for small pieces of evidence.

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Forensic Science: The Basics, Second Edition

5. Evidence placed in the pouch should be positioned to the base of the pouch.
Then the evidence fold is secured by making two folds and a tuck. First, fold
the top point down so that the remainder of the paper is in the form of a square.
Second, fold the square in half horizontally.


6. Open the rectangle. Take the folded top point and tuck
1d it into th bottom where
the two pointed end pieces cross. This secures the evidence fold. Next label the
folk and place it into an evidence envelope, labeled, and secured with evidence
tape.

tuck this inside



1e

MINI LAB 2: SKETCHING A CRIME SCENE
Once the mock crime scene is set up, your task is to make a detailed sketch of the
scene. Follow the steps below to make your rough sketch. Refer to Figure in this
chapter as an example of what should be included in a crime scene sketch.
Step 1: Locate the direction of north in your room and stand facing that direction
as you look into your scene. North should be at the top of your sketch paper,
south at the bottom, east to the right and west to the left. Placed the letter “N”
on your paper and indicate the direction of north by placing an arrow next to
the N that points to the top of your paper.
Step 2: Draw a square or rectangle on your paper to represent the sides of the
room. Measure the room dimensions in feet and inches and label the sides of
your sketch with the appropriate dimensions.
Step 3: Locate large objects that are important pieces of evidence, such as a table,
a couch, a victim, or a bed, and place them in the sketch by taking measurements. Measure a point on the object to two fixed positions (walls, countertops,
windows, doors) in the room. (See figure ) On the paper draw a picture of
the item being measured and show the dimensional measurements with lines
connecting the items to their points of measurement.
Step 4: Give each item that has been measured a number or a letter label and add
it to your sketch. Record the label and a description for your Evidence Key. For
example, Letter A-victim; Letter B-knife.
Step 5: Sketch smaller items in the scene that might be important. These items do
not necessarily have to be measured if they can be easily located in the scene.
Step 6: At the bottom of your paper create an Evidence Key that includes the letter/number labels and a short description of the item.

Crime Scene Investigation 51

Step 7: Place a heading on your sketch. Include the date and time, the address,
the name of the victim (if any), the type of crime (if known) and your name as
the “Officer.”

Further Reading
Fisher, B. A. J. Techniques of Crime Scene Investigation. 7th ed. Boca Raton, FL: CRC
Press,
Wecht, C. H. Crime Scene Investigation, Reader’s Digest. New York,
Grant, S. CSI: Crime Scene Investigation: Secret Identity. New York: IDW Publishing,

On the Web
www.crime-scene-investigator.net
www.mycriminaljustice.com
www.feinc.net/cs-inv-p.htm
http://science.howstuffworks.com/csi.htm
www.ncjrs.gov/pdffiles1/nij/pdf
www.crimeandclues.com/crimescene.htm
www.atf.treas.gov/labs/frl/index.htm

3

The Nature of Evidence

Learning Objectives









1. To be able to describe the difference between real and demonstrative evidence
2. To be able to describe the difference between known and unknown evidence
3. To be able to recognize when evidence is known and when it is unknown
4. To be able to define class evidence and individual evidence
5. To be able to determine whether a characteristic is class or individual
6. To be able to define identification and individualization
7. To be able to define and give examples of positive and negative controls
8. To be able to define false positive and false negative tests

53

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Forensic Science: The Basics, Second Edition

Chapter 3

The Nature of Evidence
Chapter Outline
Mini Glossary
Introduction
Classification of Evidence
Physical–Nonphysical Evidence
Real–Demonstrative Evidence
Known–Unknown Evidence
Individual–Class Evidence
Identification
The DNA Typing Situation
Positive and Negative Controls
Summary
Test Yourself
Further Reading

Mini Glossary
Class evidence:  Evidence that cannot be associated with one particular object or
person. It can only be put into a group of similar pieces of evidence.
Demonstrative evidence:  Evidence that does not arise from the crime itself, but
is created to illustrate or explain evidence. Crime scene drawings or photographs are examples.
Evidence:  Anything that will make an issue more or less true than it would be
without the evidence.
False negative test:  A chemical test that turns out negative even though it should
have been positive.
False positive test:  A chemical test that turns out positive even though it should
have been negative.
Identification of evidence:  The process of describing and documenting chemical,
biological, and/or physical characteristics of evidence.
Individual evidence:  Evidence that can be associated with one particular person
or object.
Known evidence:  Evidence whose source or ownership is known at the time it is
collected.
Material:  Evidence is material if it pertains to the particular case that is being
tried or investigated.
Negative control:  A material, usually a matrix, that would be expected to respond
negatively to a particular chemical test.
Nonphysical evidence:  Evidence such as eye witness or expert testimony or interpretation of an analytical test.
Physical evidence:  Evidence that consists of objects, people, or materials.

The Nature of Evidence 55

Positive control:  A material or chemical expected to respond positively to a particular chemical test.
Probative:  A piece of evidence that tends to prove or disprove a fact or assertion.
Real evidence:  Evidence generated directly from criminal activity.
Relevant:  Evidence that is both material and probative that pertains to the case at
hand and tends to prove or disprove some aspect of the case.
Unknown evidence: Evidence whose source or ownership is not known at the
time it is discovered.

Introduction
In Chapter 2, we learned that crime scene investigation is a type of reconstruction. It
is somewhat like an archaeological dig where anthropologists painstakingly search
through the scene to find evidence of who lived at the scene, when they lived there,
how they lived, and why and how they left. Sometimes we call evidence clues. Evidence
consists of hints or pieces of data that help reconstruct a scene—in our case, a crime
scene. Evidence can be thought of as something that supports or rejects a theory about
a crime, how it occurred, and who committed it. Evidence is defined in law books as
anything that would make an issue more or less likely that it would be without the evidence. Another way of expressing this would be that evidence is anything that tends to
prove or disprove something at issue. So does this mean that a crime scene investigator
should seize everything at a crime scene in the hope or presumption that it might help
prove or disprove something? More importantly, how does one decide what is evidence
and what isn’t? This is of course, partly a question of experience but more an issue of
context. A crime scene investigator will view the scene carefully to determine what
type of crime may have occurred and that knowledge will guide her in determining
what may be evidence and should be collected. Interestingly, the popularity of the TV
shows such as CSI has resulted in a situation where juries often question why some
evidence wasn’t collected (as it would have been on the show). This has caused prosecutors to direct investigators to collect practically everything—just in case.
Another concept from law also provides guidance as to which evidence should be
collected. A rule of law states that evidence must be relevant if it is to be admitted into evidence. This means that it must be material (it must pertain to the
particular crime being investigated and not some previous incident) and probative
(it must actually prove something). Thus, crime scene investigators are guided by
whether a potential piece of evidence passes or is likely to pass the relevance test.
For example, at a homicide scene where the victim was killed by being shot with
several bullets, what purpose would be served by seizing kitchen knives (assuming
they are not bloody or in the victim)? The knives wouldn’t be relevant. This concept
will be covered in more detail in Chapter

Classification of Evidence
Evidence may be categorized in a number of different ways. At first glance, one may
wonder why there should be so many different ways of categorizing it, but as it turns
out, the class or type of evidence can be very important in determining what value
it has, how it should be collected, what else should be collected (controls, exemplars)

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Forensic Science: The Basics, Second Edition

and most important, what conclusions can be drawn from a scientific examination
of the evidence. There are also legal distinctions among different types of evidence
that help determine its admissibility in court. The major classification systems for
evidence are listed and discussed below. These schemes apply to all evidence, not
just scientific or technical.
• Physical–nonphysical
• Real–demonstrative
• Known–unknown
• Individual–class

Physical–Nonphysical Evidence
Physical evidence consists of objects or things. Nonphysical evidence is verbal
testimony about a crime, or someone’s actions during a crime. If someone is seen
running away from a bank robbery holding a bag of money, the action of running
away is nonphysical evidence while the bag of money is physical evidence. The reason for discussing this somewhat obvious distinction is to emphasize that not every
piece of evidence is an object. Courtroom dramas often focus on motive—why someone would commit a crime. This can be critical evidence. A motive is often required
as an element of a crime. Sometimes the distinction can be tricky. If a witness identifies a suspect at the scene of a bank robbery, what is the evidence? The suspect?
The witness? The testimonial evidence of the identification? Suppose a polygraph
test has been administered to a suspect as a means to detect deception. A qualified
examiner interprets the polygraph chart and renders an expert opinion in court as
to the truthfulness of the suspect. What is the evidence here? The machine? The
squiggles on the chart? The testimony of the expert? Figuring out what is actually
the evidence can be tricky but is very important.

Real–Demonstrative Evidence
Real evidence is that generated by criminal activity. It is found at the crime scene
or elsewhere and pertains to the crime. It may be fingerprints left at the scene or
those obtained from a suspect. It may be drugs, blood, or bullets. Real evidence,
however, may not be found at the crime scene. If someone is shot and killed and
there is no weapon at the scene, a search of a suspect’s house may turn up the gun.
It is no less evidence because it wasn’t found at the crime scene. Of course, testing
will have to be done to prove that this gun actually fired the fatal bullets. The vast
majority of evidence in criminal cases is real evidence.
Demonstrative evidence, on the other hand, is created to help explain or clarify real evidence. It is produced after the crime and not by the crime. Crime scene
investigators always make sketches or videotapes of crime scenes and sometimes
produce scale drawings or physical models if needed. This way, the crime scene is
preserved for the jury long after it has been turned back to the owner. Increasingly,
computer simulations of events such as fires, explosions, vehicle crashes, structural
failures, and so on are produced to help determine how an incident occurred or to
reconstruct it for a judge or jury. Demonstrations may be performed to illustrate the
value or characteristics of evidence. About twenty years ago, one of the authors of
this book was involved in a civil case that involved the issue of whether a certain
hair product (a curl activator) could have caused the victim’s hair to catch on fire
when a lit match accidentally flew into her hair during the act of lighting a cigarette.

The Nature of Evidence 57

In order to answer this question, we tested many samples of hair with and without
the product, dropping lit matches into the hair and determining how long it took
for the hair to catch fire. The entire process was videotaped and the tape shown to
the jury. They were able to see that the hair product actually retarded burning. The
videotape is a classic example of demonstrative evidence.

Known–Unknown Evidence
Probably the most important question asked about evidence found at a crime scene is:
Where did this come from? In other words: From what person or object did this arise?
The value of every piece of real evidence arises from its association with someone
or something that was involved in the crime. Crime scene reconstruction depends
on making these associations. Known evidence consists of objects whose source or
ownership is known at the time it is collected at the crime scene or elsewhere. We use
the term unknown evidence to refer to evidence discovered at a crime scene that
has an unknown origin or source. A bullet found in the body of the victim of a homicide is unknown evidence. The criminal investigator is going to want to know where
this bullet came from. What gun fired it? At the time it is discovered as evidence, however, the bullet’s source is unknown. Suppose a burglar enters a house by breaking
a glass window and climbing through. On his way in, he cuts himself on the broken
glass that is still in the window, leaving some blood on the glass. Some of the broken
glass from the window falls to the ground where the burglar steps on it and gets some
imbedded in his shoe. After the crime is committed, the investigators examine the
scene and find the blood on the glass in the window. The blood is an unknown—its
source is not known to the police. The glass in the window is a known—it obviously
comes from the window. The glass on the floor around the window is an unknown. It
would be tempting to say that it must have come from that window, but there is no
proof. It could have been there since before the crime was committed. When the suspect is arrested, a search warrant may be obtained to search his house for evidence,
especially his shoes. The glass found embedded in his shoes is an unknown. It could
have come from anywhere. To find out whether it came from the broken window, it
will have to be compared with glass taken from the broken window (known evidence).
It is very important to be able to categorize evidence in this way. It guides criminal
investigators and forensic scientists in their decisions about what evidence has to be
tested and what known evidence must be collected in order to perform the tests.
Something for You to Do
Below is a crime scenario and a list of possible pieces of evidence. Identify each one as known or unknown. If the evidence
is unknown, then determine what known must be collected so that it can be compared to the unknown.
A man was walking across a street carrying a load of Christmas presents. A light blue car comes careening down the
street and hits the man with the right front fender of the car, killing him instantly. The car sped away from the scene at a high
rate of speed without stopping. A witness who saw the crash called the police with a description of the car and a partial
license plate number. A few minutes later a car matching the description was stopped by police for speeding and suspicion
of vehicular homicide. The car was then impounded. Upon inspection of the car, the crime scene investigator noted that
the right front fender was badly damaged and some paint was missing. The right front headlight was broken and part of the
glass lens was missing. The damaged area of the fender had some black fibers imbedded in it. Examination of the hit and
run scene revealed that the victim’s black coat had some light blue paint flecks imbedded in it. There were also a few flecks
of glass in the fibers of the coat. The street around the victim’s body had pieces of broken glass strewn about.
Possible evidence:
The victim’s black coat and fibers taken from it
Fibers found imbedded in the damaged fender of the suspect car
Glass taken from the broken headlight of the suspect car
Glass from the street around the victim
Glass taken from the victim’s coat
Paint chips taken from the victim’s coat
Paint taken from the damaged area of the car

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Forensic Science: The Basics, Second Edition

Individual–Class Evidence
In the previous section, we are asking questions about the origin or source of evidence. Now we must examine what types of answers can be given to these questions.
Consider, for example, a fingerprint left on a wine glass at the scene of a crime. This
might be evidence of the perpetrator’s presence at the scene. It is clearly unknown
evidence. If a suspect is identified, a fingerprint examiner can compare the print on
the wine glass with fingerprints known to be from the suspect. The question of association now becomes: With what certainty can we conclude that an unknown print
from a crime scene came from a particular finger on a particular person? For more
than a hundred years, fingerprint examiners have testified in court that a latent
fingerprint found on an object definitely came from a particular finger of a particular person. Fingerprint experts will testify that they are sure of this conclusion to
a degree of reasonable scientific certainty. Now consider a case where blue denim
fibers (blue jeans) are found on an overturned chair in a room where a dead body is
found clothed in white polyester pajamas. Later a suspect is identified who is wearing blue jeans. Fibers from these blue jeans are compared with those from the chair
at the scene in order to determine whether the jeans were the source of these fibers.
In this case, the fiber expert could only testify that blue denim fibers found at the
scene of the murder could have come from the pants worn by the suspect. Analysis of
evidence of this type cannot support a conclusion that the unknown fibers definitely
came from the blue jeans worn by the suspect. There is certainly a difference in the
conclusions reached by the scientists in these two cases. In the first case, the examiner has concluded that there is only one finger that could have left the fingerprint
on the object at the crime scene. In the other case, the examiner concludes that the
fibers are similar to those from the pants worn by the suspect, but they could also
be from another pair of pants of the same type, made of the same fibers.
Why is there a difference in the conclusions? The answer lies in the concept
of individuality and uniqueness. In the case of fingerprints, there are characteristics of each fingerprint of each person that make that print unique. The argument goes that, if there are enough of these unique characteristics in the pattern
of a latent fingerprint found on an object, then that latent print must have come
from the one single finger. The underlying principle is that all fingerprints are
measurably, demonstrably unique. This will be discussed further in the chapter
on fingerprints.
In the case of the blue denim fibers, the examiner was unable to conclude that
the fibers from the crime scene definitely came from the pair of pants worn by the
suspect. This is because the fibers in a given pair of pants are not unique. Mass production of textiles means that there are sure to be many pairs of pants made from
the same batch of fibers and there is nothing unique about any one pair. Even if the
unknown fibers from the crime scene had exactly the same characteristics as those
from the suspect’s pants, it doesn’t rule out the possibility that fibers from another
pair of pants would also match exactly.

Sours: https://docshare.tips/forensic-science_a81adb6d87f7e0a8b4cc2.html

The best books on Forensic Science

Thank you for selecting five of the best books on forensic science. I’m sure many of our readers must feel they have a notion of what forensic science is from crime novels or crime drama on television—but as you noted in our earlier correspondence, you want to get away from what you called ‘fast-food forensics’. Could you tell me more about how the image of forensic science differs from the reality?

Yes. It’s hugely different. Over recent years, television has got a bit more accurate in the procedural sense, because there are so many forensic science courses—people believe they know about managing a crime scene, cordoning things off, all that kind of stuff. But the truth of the matter is that only a tiny number of people have ever been to a crime scene or been in a forensic science lab. Only a tiny number of people have ever actually been in a court, let alone given evidence. People fill these gaps with their imaginations, and this imagination has just gone wild in the last twenty years, and a lot of it is just untrue.

The uniqueness of fingerprints, for example—we’ll get onto this when we discuss my last book choice. It’s hugely convenient to believe fingerprints to be unique. What that means is, as a witness you go into court and you’re unchallengeable. As a lawyer or a cop, you’ve got a cast-iron case. Biometrics is another good example. People are sucked in by biometrics, they just believe in this technology. It’s so much easier to believe than it is to confront the reality, which is that it sometimes works and sometimes doesn’t.

You have worked in forensics for over forty years, including on some very high profile cases. You will be publishing some of these experiences in your upcoming book, Murder Under the Microscope. But what drew you to the field initially?

You know, it’s a very disappointing answer. It was basically the only job that I was offered. We’re talking about the late 1970s when employment opportunities were pretty poor. I just took it up.

I graduated in biochemistry and wanted to work in science. But one of the ironic things is that a great deal of what we call forensic science is only vaguely science. If you go in as a scientist, if you’re actually interested in science—things that happen in labs, and the kind of techniques and models that scientists use—then your first exposure to big chunks of forensic science is hugely disappointing. Because it’s highly subjective; often quite poor science in many instances, and in some instances no science at all.

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There are, of course, exceptions. DNA is an exception. Chemical identity—identifying drugs, and things like that—is an exception. But a good deal of the rest of it, and this is a big theme of my writing, is craft. It’s a craft you can learn, it’s a craft you can be good at or bad at. It’s a craft you can make mistakes in. But, of course, the minute you have the title ‘forensic scientist’, people assume you have the authority of science behind you.

The courts treat science as a different species of knowledge. Because you have more authority, you’re harder to tackle as an expert witness. So, it’s very comfortable if you can get away with it. But actually, some quite simple questions can quickly undo the credentials of an expert or their evidence. Now, scientific evidence can be useful, but it has limits. And, of course, a lot of fictional representations don’t recognise those limits, and that’s where people get the bulk of their information on forensic science from.

The first forensic science book that you want to recommend is, I believe, a personal favourite. This is The Killer of Little Shepherds: A True Crime Story and The Birth of Forensic Science by—a past Five Books interviewee—Douglas Starr.

It tells two intertwined narratives: one is this really horrific serial killing in 19th-century France; it also tells you about the origins of forensic science and policing. If you go back to the early 1800s, that was the time when police forces around the world were being organised. Up until then it was private—just people who were hired as security, with no formal legal basis.

So The Killer of Little Shepherds is set around the time that the Sûreté was formed…

…the French criminal investigation bureau…

…and a man called Vidocq became a very famous detective. He’s kind of a French equivalent to Sherlock Holmes, although Sherlock Holmes is fictional while Vidocq was a real person.

It’s a horrific story, even by my standards: a man killed 11 people—mainly children or teenagers, boys and girls—and disembowelled them and raped some of them. He moved around southern France, and sometimes outside of the south of France. This is one of the big lessons which resonates with my career. Even in modern times police forces are not that good at cooperating. I’m not saying they don’t cooperate, but personalities often get in the way; everybody wants to solve the case. There are tensions and rivalries as you see in any other organisation. So one of the reasons this man could act under the radar was because he moved around. When it was happening in a different place or legal area, it became somebody else’s problem. Eventually he was caught more or less red-handed.

“A great deal of what we call ‘forensic science’ is only vaguely science”

In the French case, a man called Lacassagne, who was a professor of forensic medicine at Lyon University, played an important role. He was the tutor of an Edmond Locard, considered by many—not quite accurately—to be the founding father of modern forensic science. But he was one of Lacassagne’s pupils. Lacassagne was saying things like: ‘pay attention to details’, ‘observe carefully’, ‘try to be objective, theorise, then test the theory’, while the cops of the time, would just be running in and splashing about, knocking things over.

The things that really struck me about this book were that it’s really well written, incredibly well researched, and it’s a fantastic story.

What more could you ask of a book?

Douglas Starr is an American who started as a journalist. How he researched it in France… he must be a fluent French speaker, or reader, anyway. Many of the problems that arise in this case I highlight in cases in my book, which will be published in October, of recent cold cases. For example, Robert Black killed four children in the UK between 1981 and 1986 before he was arrested and convicted. One of the reasons he was able to do this was because he moved around the country operating in different police force areas.

People are still making mistakes or forgetting things, not cooperating, misunderstanding or not paying attention to the evidence, and so on and so forth.

Alexandre Lacassagne, wasn’t he the originator of the study of blood spatter?

He contributed to the development of blood pattern analysis. But these things weren’t happening around the time of the book. People were only just beginning to see that blood spatter might tell us how a person died, whether the body was moved, what weapon was used, stuff like that.

Lacassagne was a medic, a professor of what he called criminology. He was more focused on bodies, but he was also interested in things way beyond that.

You mentioned earlier the taping-off of crime scenes. I think this is the starting point for our next book on forensic science, Murder and the Making of English CSI. It’s by Ian Burney and Neil Pemberton.

They write the history of this notion of a ‘crime scene’—as a special place, a social creation, as an idea. They explained something to me that I’ve always struggled to explain to other people, which is: what’s a crime scene like? What can a crime scene be? My answer now would be, well, a crime scene is an idea, a concept. It can be anything you want. It can be a spaceship, it can be a car.

As a scientist, I work very closely with social scientists; much of my research nowadays is in the hinterland between natural sciences and social sciences. And this book explained things to me that I’ve misunderstood for a very long time.

They take only two crime scenes, but they look at them in a great deal of detail. They point out words and phrases that we now use routinely and assume that everyone understands them. So: the whole notion of a crime scene as a geographic location where something happens. They talk about how we demarcate it and start to look at it; how different roles start to develop for looking at different bits of it; how people start to take notes and record diagrams. How all that requires some kind of cooperation and discipline and structure—counter to most crime novels, or at least a certain genre of crime novels where you have the ‘great man’, the detective who comes in and somehow sees things that no one else can see.

“Crime scenes are not just procedural. They’re cognitive, too”

Burney and Pemberton point out that it is, in fact, a collective enterprise. Yes, people have insights, but the bottom line is: people can get it wrong. The way you keep on track is usually to expose your ideas to some kind of reflection or criticism, to talk to people.

And they say something very explicitly: that crime scenes are not just procedural. They’re cognitive, too. You look at them and think: ‘how would somebody get in here?’ or ‘how would you get out of here?’ You can come up with some really crazy theories, test them and then abandon them…. That’s quite a complicated business to do in a group. I’ve been in briefings where people have come up with absolutely wild ideas, and you want to say that to them—but you let it run. The evidence will eliminate it eventually, and they will quieten down.

Between the 1920s and 1950s, you get the development of the murder bag: the case, the kit with forceps, bags to put things in, and labelling, and the chain of custody. These are all ideas that were consolidated in this period. Continental Europe was way ahead at this time. A man called Hans Gross—whose name seems to have been forgotten in the UK—was really the first person who thought about the whole business of a ‘crime scene investigator’ who pays attention and thinks and hypothesises, and then tests those hypotheses. A very rigorous, rational kind of process.

I think they also look at what they call ‘body-centred’ forensics.

Yes. As I’ve written myself, a body is a defining feature in a crime scene. If you go to a murder scene and there’s no body, then it’s a murder scene and you get on with it. But if there’s a body there it changes the whole thing.

Firstly, it brings in a certain practical urgency, because everyone’s waiting for the body to be taken away for a post-mortem examination. Also, you see the context and—as a blood pattern expert—I would always say I need to be there when the body’s there, to see exactly where it was. But quite often this isn’t possible.

The body—in a homicide—is the literal embodiment of the crime. So there are all these practical and cognitive, imaginative things associated with it.

Does a forensic scientist work closely with forensic pathologists? Is there much interplay between these two roles?

Yes. As a biologist, I would. Most of the work I’ve done would be in what are legally termed ‘offenses against the person’. If I were a chemist, I would do more road traffic accidents, blood alcohol analysis or burglaries (shoe marks, glass fragments), whereas most of my work was in sexual assault and homicide, all of which is dealt with in the higher courts.

So, yes, I worked with pathologists and I would very often want to know what injuries a person had sustained, to make sense of how blood was distributed on clothing or on a weapon. Sometimes I worked with them very closely, at the post mortem, and sometimes remotely via phone call, or reading a statement or report.

Let’s move onto book three, which is Maggie Nelson’s The Red Parts: Autobiography of a Trial. I love Maggie Nelson’s writing—her beautiful fragmentary memoirs Bluets and The Argonauts—but they are very concerned with literature and philosophy and art. I’m not sure I ever expected her to turn up on a list of forensic science books! Tell me about The Red Parts, and why you have chosen to include it among your reading recommendations.

I can’t possibly do justice to this book. I really can’t. It’s such an extraordinary book. She exposes herself as a writer and as a person. There’s no boundary for her whatsoever.

We are very much in the modern world, in cold-case review territory. I think this was published in 2007. It’s an extremely candid memoir, written by someone directly involved in a murder case—the victim was her aunt. But also, because of the timing (she comes into the case 35 years later), she can be a dispassionate observer as well.

So, Nelson’s aunt was a first-year law student who was brutally murdered in 1969. It was an unsolved crime for decades, but was reopened in 2004 when a DNA match identified a new suspect. Nelson had previously written about the shadow this horrible crime cast upon her family in Jane: A Murder.

Yes. In The Red Parts, she goes to court, she meets the cops, she sits through the trial. She talks about the decision whether to go to court or not, whether to look at the images of the post-mortem, which are being projected onto the court wall. She describes all the primary materials, sometimes in a very factual way—and then she goes on to engage with them in a very different and emotional way. It’s beautifully written.

One thing that really resonated with me was when she talks about how many people are just completely unwilling to face their revulsion about what’s happened in cases. We’re just completely unwilling to confront the fact that someone has done something to someone else which we cannot possibly conceive of. I don’t recall exactly what she says on this, but my take on it is that many people immediately resort to the notion of evil, which puts clear water between this and humanity. You know: ‘They’re evil, and therefore I don’t need to worry about it because I’m not evil.’ We can rationalise it away.

“Nelson expected to be confronted with a monster, and she just sees this innocuous person”

There’s an interesting link to Hannah Arendt, the philosopher. She used the phrase “the banality of evil” to describe Eichmann during his trial in Israel. Maggie Nelson writes: “Where I imagined I might find the ‘face of evil,’ I am finding the face of Elmer Fudd.” She’s saying the same thing: she expected to be confronted with a monster, and she just sees this innocuous person and doesn’t know what to make of it.

She comes up with this idea of bearing witness to the routine of the state: this process as a machine of prosecution and justice. All of this had enormous resonance for me. It’s a fantastic book—of the five, it’s probably my favourite.

It’s interesting that you selected it, given that you are an expert in the field. What did you take from reading a layperson’s account of a trial? Is it important to understand the emotional stakes, on the part of the victim and/or their family?

One of the things you have to learn quickly—or at least, I did—is that emotions should have little part to play in the work, although I can now engage with them in my writing. Not in the way that Maggie Nelson has, but at least to recognise them.

While writing, I came across some really interesting cases that show that the police are far more emotionally driven than they would ever admit. There’s one case in particular—the murder of Rachel Nickell—where it’s very plain to me, having researched and written about it, that the a key driver of the investigation was affect. It wasn’t rationality—it was just the horror of the case. So emotion plays an enormous part here.

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I imagine it is no different to being a nurse or a doctor: if you get hugely emotionally engaged with your patient, I can’t imagine you would do your job very well. So you do need to manage that, I guess, otherwise you end up like some people I know who, thirty years into the job, end up with PTSD. They get flashbacks of crime scenes they were at.

Maggie Nelson is a layperson, but is also a very good observer. She used lots of factual stuff, but at its foundation it’s sort of ethnographic. She saw and she watched and she reflected. She doesn’t give us any flights of fancy in here—that’s not to say she didn’t use her imagination. What’s in this are some very pointed reflections on what people did then, what they are doing now, whether this process was the right thing to do, whether you should confront it or run away from it.

It’s also riven with family tensions. The big issue is whether they’re going to be in court for the verdict: guilty or not guilty. She describes the tension in that process. She’s just a great writer.

Fantastic. Well let’s look at book four on your forensic science reading list. This is Killer in the Shadows: The Monstrous Crimes of Robert Napper by Laurence Alison and Marie Eyre. This book deals with a case that you just mentioned, the brutal murder of Rachel Nickell and a related miscarriage of justice.

Yes, it’s a big chunk of my next book. But yes, Rachel Nickell was killed on Wimbledon Common in 1992. I got involved in 2006, I think.

Napper killed Rachel Nickell, he stabbed her 47 times. He was still stabbing her after she was dead. In broad daylight, in the middle of London on a summer’s day. She had her two-year-old son with her at the time.

And the police absolutely fucked up the investigation, pretty much from top to bottom: fitted someone up. They used this man called Paul Britton who was a forensic… let’s call him an offender profiler, which is a term they used then, but nobody would use now. Britton was naïve, but the cops were the opposite of naïve. This profile led them to Colin Stagg, and they just put on their blinkers after that and didn’t listen to anything else.

“The police absolutely fucked up the investigation, pretty much from top to bottom”

Stagg was tried at the Old Bailey in 1994, but the judge kicked out the case. He was just appalled by it. He really leaned on the police and the prosecution. He obviously thought the case was nuts and should never have brought near a court. Then the case remained unsolved.

Apart from the Stephen Lawrence case, it was the single biggest investigative failing in the many failings of the Metropolitan Police. I used to work in the Metropolitan Police forensic lab.

Now, in 2006 I was asked to review this case. Napper had actually killed another woman the year after Nickell: Samantha Bisset and her four-year-old daughter, in absolutely horrific circumstances. So horrific that at least one of the persons at the crime scene never worked again. Utterly horrific.

Just awful.

The upshot of the story is that Napper came to court in 2008. Napper is now in Broadmoor.

This is the high security psychiatric hospital in England, where a number of notorious murderers have been detained.

There was no trial. He pleaded guilty to the murder with diminished responsibility. By that time he had already been convicted of the previous murders. They reckon he could have raped as many as 100 women. Given what we were saying earlier, it’s interesting that they used, as a subtitle, ‘The Monstrous Crimes of Robert Napper.’ I think most people would have no trouble in describing Napper as a monster.

Laurence Alison and Marie Eyre, I think Alison’s student at the time, are much more interested in Napper than the crime; I was reviewing the crime—although I always want to try to figure out what he was doing. During my review I had a really smart detective from the Met who was my interlocutor; they wanted an independent review because they had had so many problems with the case. The main problem was that evidence could potentially have been contaminated, because they didn’t know cases from Napper were actually in the lab at the same time as the original Nickell case—because they hadn’t linked the cases.

The situation in the lab was so bad, that when they told me what had happened I basically thought to myself: ‘You’re fucked. There’s no way on Earth this can’t be contamination.’ Then they said to me: ‘If you say this is potentially contamination, there will be no trial, no prosecution.’ So no pressure then!

But at the end of the case, when I’d reviewed it—and it was a horrifically detailed and complex thing to do—I decided that it probably wasn’t contamination. I couldn’t possibly rule it out. You can almost never rule out contamination, there’s always the possibility, but it was unlikely.

“This guy targeted women with children. That’s really, incredibly unusual”

It takes a long time to get your head around these cases. There’s a huge difference between getting directly involved in a case and going to the scene and seeing it first hand, and just having a lot of documents and photographs. So I was constantly meeting up with the Met detective to ask, ‘what about this?’ and ‘what about that?’

There was an interesting conversation we had while I was building up for my review, when I said to him one day: ‘this guy targets women with children. That’s really, incredibly unusual. I’ve never come across this before.’ And he told me, smiling, ‘I’ve been told not to discuss that part of the case with you, because we want a completely independent review.’ I said, well, I didn’t need to know, I really didn’t. But it seems to be rather obvious.

All the documents in the case were disclosed to me. To my surprise this included correspondence between the Home Office, the police, the Crown Prosecution Service and the Forensic Science Service (FSS), who had carried out the early forensic work. Later the police transferred the case to another forensic lab, which found DNA evidence that the FSS had missed. The case papers showed how the FSS tried to cover up their failings. I also got the distinct impression that the Home Office were trying to distance themselves from the row because they were concerned that it might impact on the planned privatization of the FSS.

Alison really opens up what might be in the mind of Napper. And we can only speculate, but it’s a very dark place, a very strange world, where there’s this connection between sex and horrific violence and humiliation and torture. It’s pretty horrible.

I’ve used a quote from Alison as an epigraph. Because in the outside world these people are described as monsters who are hiding in the dark shadows. But Alison says, no. They’re right in front of you. There are serial killers there in plain sight. I thought, oh, that’s cute. That’s much more chilling that the man hiding in the shadows. Napper worked as a cleaner in a school. They all thought he was a bit odd, sure. But there he was in plain sight.

What a horrifying case. You’ve touched on this a little already, but could you talk about the risk of post-traumatic stress in this job, and what you have to deal with on a day-to-day basis? I mean, is this something that a person considering going into the field should worry about?

I wouldn’t over-worry about it, because you are a bit remote from the really serious action. You do have to go to crime scenes, and there are bodies—and some of those bodies can be in pretty horrible circumstances. But that’s only a certain type of forensic scientist.

Nobody would ever make you go to a crime scene. You could choose not to. It would curtail your work a bit, but the people who really tend to suffer from PTSD are cops and crime scene investigators who see this day in, day out.

How many bodies have I seen throughout my career? Not that many, to be honest. I don’t know how many, but perhaps only 30. I’ve seen some pretty horrible photographs—and even photographs could set you off. But even then… it’s a subset of a subset of forensic scientists who get exposed to this kind of stuff, whereas cops and crime scene investigators and pathologists are exposed all the time. So I don’t think it’s a huge problem for forensic scientists.

“If you engage in a highly emotional way, you are probably in the wrong business”

But if you have that personality type, where you engage in a highly emotional way, you are probably in the wrong business. You do need to be able to distance yourself from this. You need to be able to cope with the details of how somebody might have been raped or tortured or murdered, and you need to be able to listen to what has happened and think: ‘what does that mean for my investigation?’ Only on a tiny number of occasions have I been involved in cases where I’ve heard the details about a case and felt that I didn’t want to hear any more.

In the Robert Black case—a serial child killer—I had to think: ‘what has he done to these children?’ And I can remember myself just thinking: no. A bit of me was saying: ‘You really don’t want to think about this.’ But it would tend to be cops who get the real brunt of this because they deal with the victims—and the offenders, you know, people who will lie to you, and boast or brag, when you believe they’re guilty. So that’s a much trickier psychological environment than just reading the story in a case file.

And, I suppose, these extreme cases like Robert Napper or Robert Black must come up relatively rarely.

Oh, yes. I mean, I’m not sure how many serial killers I’ve dealt with, but you could count them on one hand, probably. They’re pretty rare. Whereas if you pick up a crime fiction book, every second book has a serial killer. There soon won’t be any people left!

Great, so we’ve made it to book number five, and we’re retaking our thread of the history of forensic science. This is Suspect Identities: A History of Fingerprinting and Criminal Identification, by Simon Cole.

Yes. This, for me, completes the circle—although things have moved on a bit since 2001, when this was published. It’s a more academic book—I mean, it’s very readable, it’s not an academic treatise, but I guess unless you’re really interested then you might think it a bit dry. But he’s a very good writer and he has good sources. What he asks is: how did we get to this idea that we can identify people? Where did it come from, how do we do it, and does it work? That’s the short of it.

We need to identify people because if you’re going to put somebody in prison, or even accuse them of a crime, we need to be confident it is the right person. So it’s a really important aspect of criminal justice. Most people don’t realise that, actually, most fingerprint identification is simply used to confirm the identify an offender when they are arrested.

“The idea caught everyone’s imagination: that you can measure the body, and that can be used to identify a person”

What Cole does, is he goes right back to Bertillon. Bertillon was the French anthropometrist who believed you could identify a person by measuring the body; he took photographs and he would measure noses, eye distances, all that—early ‘facial recognition’ stuff. But this was completely impractical. You couldn’t store this stuff and identify people quickly enough. So it was quite quickly supplanted by fingerprints, because they were left at crime scenes. Not many criminals leave photographs at crime scenes, or at least not before CCTV!

But the idea caught everyone’s imagination: that you can measure the body, and that can be used to identify a person. So Cole goes through Bertillon, and some other quite scary people like Lombardo, who would say that ‘the shape of the skull tells you that this person is a criminal’—all this eugenics stuff.

Along come fingerprints, and there are eugenicists involved in that as well. Francis Galton, Darwin’s cousin, was a huge eugenicist, he believed in a criminal ‘type’.

Right. Galton made a composite images of ‘the face of crime’ by combining the faces of lots of different criminals. He thought that if you looked like the composite face, you were more likely to become a criminal.

If you go back to the time of The Killer of Little Shepherds, or a little earlier, this was a time when you got these huge movements of population, immigrants moving from the countryside to the cities. There was more crime, and they wanted to identify criminals. Everything was getting organised, systematised—all these policing organisations were being developed.

So Cole goes over the history of all this, and dissects the connections between this and the emerging belief in uniqueness—that your face is unique, for example. But even if your face is unique, in modern facial recognition the measurement of your face requires a machine, and a machine is created by a human, and inside the machine is an algorithm written by a human, and its output is interpreted by a human. None of these things are perfect.

Yes, we’re beginning to hear a lot of these stories of bias in algorithms used in artificial intelligence and machine learning systems too.

They’re all subject to error. But uniqueness was just such an enormously convenient idea. So what happened—in the 1930s, in Scotland, and there was a kind of parallel evolution elsewhere—it was asserted that fingerprints were unique, and are therefore infallible.

Actually, that doesn’t logically follow. There was a legal judgement in the thirties in Scotland where the judge said, ‘well, you know, I don’t like you saying these things are infallible, because nothing is infallible.’ He should just have stopped there, but he went on to say, ‘but I guess they’re practically infallible…’ No! Science doesn’t deal with uniqueness. That’s not a scientific question. To establish uniqueness in any real way, you would have to measure everything.

The second thing is, you don’t need it. I mean, I’ve gathered evidence, I’ve given really important evidence in many criminal trials which was nothing like unique. It was highly arguable. But it was on point, it went to the heart of the case: did this happen, or did that happen? Was this person there? Or was someone else there? The courts don’t need uniqueness, they never have. But it’s enormously convenient.

“The Shirley McKie case opened up this whole argument over the uniqueness of fingerprints”

Cole exposes all this really quite well. There’s a little vignette in my book, where I describe meeting a fingerprint expert at the Old Bailey, and he spends all his time telling me how unimportant my evidence is, and how important his evidence is—because it’s conclusive. Which is just another word for ‘unique’.

I was quite young and thought, well, surely they wouldn’t call me to court if my evidence was of no relevance. The courts are quite busy; they only call witnesses that have something to say. When I went back to the lab, I told my colleagues and they all just burst out laughing. They said, ‘He’s one of the mad fingerprint people who think they’ve got the answer to everything.’ It’s just dogma, it’s just faith. No science in it at all.

Why is this significant? Well, have you heard of Shirley McKie? Or Brandon Mayfield. These are the two big cases. Shirley McKie was a Scottish police officer who was accused of leaving a fingerprint at a scene. She didn’t, she was never at the scene. It was a mistake by the fingerprint experts. The debate was a huge problem, went on for more than a decade, and eventually the Scottish Government paid out more than £750,000 to Shirley McKie. That opened up this whole argument over the uniqueness of fingerprints, and error, accuracy, faith and dogma and exposed the whole thing.

The Brandon Mayfield case had some very interesting background factors—he was a US citizen and a Muslim, which I’m convinced had a bearing. The Madrid Bombing of 2006 was a horrific bombing that killed well over 100 people. The Spanish government’s criminal justice authority sent out all these fingerprints that they found associated with the crime. One went to the FBI, and they identified this American Muslim lawyer called Brandon Mayfield.

“Nine times out of ten, eight times out of ten, the forensic evidence is useful but not critical”

The Spanish experts eventually say, ‘we think the fingerprint is from another guy, who happens to be an Islamic terrorist.’ But the FBI says, ‘no, no, no. You’ve got it all wrong. It’s this guy—Brandon Mayfield.’ Eventually they have to admit they’ve made a complete error, they’re absolutely wrong. There goes the infallibility of fingerprints. They have to pay out $2 million for making an unfounded accusation. There’s a huge fuss about it, all around the world—as Paul Simon had called it, many years ago—the myth of fingerprints. The bubble had burst.

Since then, the whole business of fingerprints has been cooling. There’s been an enormous transformation from this dogmatic belief, to what it should be: fingerprints are a perfectly good way of identifying people, but you need to be honest. Sometimes errors are made, and you need to pay attention to certain kinds of cases which are problematic.

Almost all the misidentified fingerprint cases involve difficult fingerprints to deal with. They’re slightly distorted, things like that. They require a very careful procedure to make sure you’re not biased. What happened in the Mayfield and McKie cases was that they made mistakes and then they dug in. So that’s the link back.

Yes, this does seem to be an overarching theme. So, as we proceed with DNA evidence and ever more cutting edge technology, is this history being presented as a way of telling us to proceed with caution?

There’s an element of that. The problem is that forensic science is seen as this monolithic body of knowledge, and it isn’t. What is?

So the first question you should ask is, what kind of forensic science is involved? If you say DNA, most DNA profiling is pretty safe stuff. Not perfect, but pretty safe. This is amongst the best evidence that you will get in a court case. But that’s only a certain type of DNA. All the new science that’s coming out, you have to treat it with caution, as you say. You have to be careful.

DNA mixtures, which are very common in sexual offences, are much more complicated and require much more caution, like the distorted fingerprints. So you should never just believe this stuff, nor should you automatically disbelieve it. You should ask fairly seriously questions about the science—and here’s the thing—and the person (the expert witness) who’s telling you the story. Because some people have credible credentials, and other people haven’t. Even the people with credible credentials sometimes make mistakes.

So you have to unpack it: Why do you believe this? Why do you believe that? That’s what should happen in a good court case. Although things only seem to go wrong in forensic science when the evidence is really important. Then, because then everybody digs in, there is a really deep argument. But nine times out of ten, eight times out of ten, the forensic evidence is useful but not critical. You know: you get a DNA match from a crime scene, it leads you to an offender, then you establish that there are a couple of witnesses that link the offender to the crime scene and he drives the same kind of car. You’ve got a partial numberplate. Then, the DNA evidence is what I would call ‘investigative evidence’: it takes you to someone. It’s not the case against them, it’s only part of the story.

So: caution, yes. Honest scepticism is what you need in all these instances, and that’s something that can be missing quite a lot of the time.

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7 Popular Books About Forensic Science

'Criminalistics: An Introduction to Forensic Science'

This book by Richard Saferstein is an excellent guide for the nonscientific reader. It explores how forensic science is applied to criminal investigations, the techniques used, current terminology, and standard practices in crime laboratories.

The book also offers an interactive crime scene CD-ROM that allows readers to participate as investigators while a crime is being solved. This is a good resource for anyone interested in the fields of forensics and criminal justice.

'The Casebook of Forensic Detection'

Author Colin Evans' book gives readers a chance to delve into 100 investigations and learn how experts from various forensic fields used their knowledge to solve the cases. It's a great book for beginners to seasoned veterans interested in reading how specific cases were solved using the science of forensics.

'Forensic Pathology'

This medicolegal textbook was written by Vincent J.M. DiMaio, a pathologist who was the chief medical examiner for Bexar County, Texas, and Dominick DiMaio, a pathologist and former chief medical examiner for New York City. Its topics deal with time of death, blunt trauma wounds, and airplane crashes. The book, written for medical and investigative professionals, presents an overview of medicolegal investigative systems. 

'Practical Homicide Investigation'

Vernon Geberth wrote an excellent guide for anyone involved in homicide investigation and for newcomers to the field of forensic science. This latest edition offers new and revised chapters including case histories and techniques that reflect the latest forensic methods and modern investigative procedures.

"Geberth, the worldwide expert on homicide investigation, is the real thing," wrote Edwin T. Dreher, retired deputy chief of detectives for the New York City Police Department. "His chapter on DNA is one of the most readable and comprehensive treatments on the subject."

'Practical Homicide Investigation: Checklist and Field Guide'

Geberth also wrote this how-to guide that offers readers checklists and step-by-step guidelines on procedures, tactics, and forensic techniques used in sudden and violent death investigations.

The appendix categorizes evidence by type so that officers working in the field, for example, can quickly find the correct procedure for collecting evidence that they have never dealt with. It also contains multiple checklists to help ensure that proper procedures are followed and investigations are completed.

'Gunshot Wounds'

Vincent J.M. DiMaio's "Gunshot Wounds: Practical Aspects of Firearms, Ballistics, and Forensic Techniques" contains numerous photographs of victims who died from gunshot wounds plus lengthy discussions and references to the forensic study of such wounds and weapon identification.

The third edition of "Gunshot Wounds" provides readers with the latest and most comprehensive information on firearms and best practices for examining firearm-related wounds.

'Interpretation of Bloodstain Evidence at Crime Scenes'

Editors William G. Eckert and Stuart H. James complied this popular book, now in its second edition, which delves into such topics as bloodstain interpretation; low-velocity impact and angular considerations; medium and high-velocity impact; and partially dried, clotted, aged, and physically altered bloodstains. Another chapter deals with luminol. a chemical that reveals invisible blood traces. 

One reviewer said, "Anyone involved in law enforcement or criminal law will cherish this informative, well written text. It takes a very complicated, mind-numbing subject and pilots the reader in an organized, comprehensible manner to a well-rounded understanding of the subject. This one should be required reading for all law students and criminal law practitioners."

Sours: https://www.thoughtco.com/popular-books-about-forensic-science-970959
Introduction to Forensic Science

Forensic Science: A Beginner's Guide

In the wake of the phenomenal success of such shows as CSI, forensic science has never been so popular. The obsessive attention to detail that Grissom and his crew afford seemingly insignificant details, such as particles of dirt in a bullet wound and the presence of pollen in tyre tracks, have had audiences eager to know more. Siegel’s study follows the course of evidenceIn the wake of the phenomenal success of such shows as CSI, forensic science has never been so popular. The obsessive attention to detail that Grissom and his crew afford seemingly insignificant details, such as particles of dirt in a bullet wound and the presence of pollen in tyre tracks, have had audiences eager to know more. Siegel’s study follows the course of evidence all the way from the crime scene right through to the court judgement, investigating the many types of evidence, how they occur in crimes, how they are collected and analyzed by scientists, and how the results are presented in court. Packed with real examples, the book covers all the major areas of forensic science including drugs, trace evidence, pathology, entomology, odontology, anthropology, crime scene investigation, and law....more

Paperback, 192 pages

Published May 1st 2009 by Oneworld Publications

Sours: https://www.goodreads.com/book/show/5848623-forensic-science

Science books for beginners forensic

Forensic Science: A Beginner's Guide

In the wake of the phenomenal success of such shows as CSI, forensic science has never been so popular. The obsessive attention to detail that Grissom and his crew afford seemingly insignificant details, such as particles of dirt in a bullet wound and the presence of pollen in tyre tracks, have had audiences eager to know more. Siegel’s study follows the course of evidenceIn the wake of the phenomenal success of such shows as CSI, forensic science has never been so popular. The obsessive attention to detail that Grissom and his crew afford seemingly insignificant details, such as particles of dirt in a bullet wound and the presence of pollen in tyre tracks, have had audiences eager to know more. Siegel’s study follows the course of evidence all the way from the crime scene right through to the court judgement, investigating the many types of evidence, how they occur in crimes, how they are collected and analyzed by scientists, and how the results are presented in court. Packed with real examples, the book covers all the major areas of forensic science including drugs, trace evidence, pathology, entomology, odontology, anthropology, crime scene investigation, and lawmore

Paperback, pages

Published May 1st by Oneworld Publications

Sours: https://www.goodreads.com/book/show/forensic-science
Let's Talk About Death: The Best Forensic Science and True Crime Books- Reading Recommendations

Thoughts ran through my head that I would now like to take it into my mouth, but suddenly a velvet voice. Ordered: - Spin around you, I want to look at you. I turned around, seed on my fingertips.

Now discussing:

I grabbed her tightly with both hands. Her lips were salty with tears and hot with desire. We tumbled onto the bed. I slowly lowered myself to her neck, which exuded the scent of my favorite perfume.



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