Transcript Forensic Science Criminalistics Chapter 1: Introduction What is Forensic Science? The application of science and technology to those criminal and civil laws that are enforced by.

Forensic Science
Criminalistics
Chapter 1:
Introduction
What is Forensic Science?
The application of science and technology to
those criminal and civil laws that are
enforced by police agencies in a criminal
justice system.
Major Sciences Involved in
Forensics

Chemistry:


examines the chemical makeup of substances
found at the crime scene
Biology:

examines the biological properties of
substances found at the crime scene
Major Sciences Involved in
Forensics

Physics:


examines the movement or impact of
materials at the crime scene
Geology:

examines the earth’s components when
important to the crime scene investigation
History of Forensics

Sir Arthur Conan Doyle
Fictional character –Sherlock Holmes
 The character, Sherlock Holmes, first applied
these principles in Doyle’s novels:

 Serology
 Fingerprinting
 Firearm
Identification
 Questioned-document examination
History of Forensics

Mathieu Orfila (1787-1853)
Father of Forensic Toxicology
 Spanish native—taught medicine in France
 Published “The Detection of Poisons and
Their Effects on Animals” which established
Forensic Toxicology as a legitimate scientific
endeavor

History of Forensics

Alphonse Bertillon (1853-1914)
Father of Personal Identification or Criminal
Identification
 The science of anthropometry: a systematic
method of taking body measurements
 Anthropometry was eventually replaced by
fingerprinting in the early 1900s

History of Forensics

Francis Galton (1822-1911)
Studied fingerprints and developed a method
of classifying them
 Proved the uniqueness of individual
fingerprints and their use for personal
identification
 His ideas describe the principles used today
in fingerprinting

History of Forensics

Leone Lattes (1887-1954)
Developed the concept that blood typing
could be a useful identification tool in criminal
investigation
 Devised a simple procedure for determining
the blood group from a dried blood stain

History of Forensics

Calvin Goddard (1891-1955)
Colonel in the United States Army
 First used the Comparison Microscope to
determine if a bullet had been fired from a
certain firearm
 Established the Comparison Microscope as
an indispensable tool in forensic
investigations

History of Forensics

Albert S. Osborn (1858-1946)
Development of the fundamental principles of
document examination
 Was responsible for the acceptance of
document examinations as scientific evidence
by courts of law
 Authored “Questioned Documents” –a book
still used in the field of document examination
today

History of Forensics

Walter McCrone (1916-2002)
Applied using microscopes to all fields of
forensic investigations
 Taught numerous forensic scientists how to
use quantitative analysis methods in forensic
investigations

History of Forensics

Hans Gross (1847-1915)
Authored the first treatise describing the
application of scientific disciplines to the field
of criminal investigation
 Detailed the assistance that investigators
could expect from the numerous fields of
science

History of Forensics

Edmond Locard (1877-1966)
Strong advocate of the use of the scientific
method in criminal investigation
 Background in Medicine and in Law
 Taught how scientific principles could be
developed into a workable crime laboratory
 Famous for Locard’s Exchange Principle

Locard’s Exchange Principle
The exchange of materials between two
objects that occurs whenever two objects
come into contact with one another
Locard’s Exchange Principle

Examples:
Metal particles carried on clothing from a
crime scene can link a suspect to a crime
 Soil samples found on the vehicle of a
suspect can link the suspect to a crime scene
 Plant material found on cars or clothing can
link a suspect to a crime scene

Beginnings of Crime Labs

The oldest crime lab in the United States
was established by the Los Angeles Police
Department in 1923 under the Director
August Vollmer
The Federal Bureau of
Investigation
1932
 Director: J. Edgar Hoover
 Organized a national crime laboratory to
provide forensic services to all law
enforcement agencies in the country

The Federal Bureau of
Investigation
The FBI Laboratory is now the world’s
largest forensic laboratory, performing over
one million examinations per year
The Federal Bureau of
Investigation

Opened the Forensic Science Research
and Training Center in 1981

Center is dedicated to conducting
research and developing new and reliable
scientific methods that can be applied to
forensic science
The Organization of a
Crime Laboratory
Crime Labs

Can be under the direction of …
The Police Department
 The Prosecutors or District Attorney’s Office
 The Coroner or Medical Examiner’s Office
 Universities as independent testing facilities

Crime Labs
Range in size and in the number of staff
members
 Can be classified under several
jurisdictions

Federal
 State
 County
 Municipal

Crime Labs

There are approximately 320 public crime
labs operating in various jurisdictions

These crime labs range being able to
perform a diversity of tasks to very
specialized scientific testing
Growth of the Crime Lab

Some Reasons:
Courts placing greater emphasis on scientific
evidence
 Emphasis on thorough and complete police
investigations
 Increase in modern technology and types of
testing that can be completed

Growth of the Crime Lab

Major Reasons:

Increase in the crime rates in the United
States
 Even
though many crimes do not require forensic
evaluation of evidence
Growth of the Crime Lab

Major Reasons:

The increased number of drug-related arrests
 All
seizures must be sent to the lab for
confirmation of chemical composition of the
substance
 More drug arrests=Larger case loads of drugrelated specimens
Growth of the Crime Lab

Major Reasons:

The advent of DNA Profiling
 Labor-intensive



tests for DNA analysis
May come from blood evidence
May come from saliva or other bodily fluids
May come from bite marks, cigarette butts, hair, etc.
Federal Crime Labs in the U.S.
Will assist any local agency that requests
assistance in investigative matters
Federal Crime Labs in the U.S.

Federal Bureau of Investigation (FBI)
Housed under the Department of Justice
 Responsibilities:

 Broad,
investigative powers that exceed
jurisdictions of state and local authorities
 Expertise and technology support for criminal
investigations
Federal Crime Labs in the U.S.

Drug Enforcement Agency (DEA)
Housed under The Department of Justice
 Responsibilities

 Analysis
of drugs seized in violation of federal laws
that regulate the production, sale, and
transportation of drugs in the U.S.
Federal Crime Labs in the U.S.
Bureau of Alcohol, Tobacco, Firearms, and
Explosives (ATF)
 Housed under The Department of Justice


Responsibilities:
 Analyzing
alcoholic beverages and documents
relating to tax law enforcement
 Examining weapons, explosive devices, and
evidence relating to the Gun Control Act of 1968
and the Organized Crime Control Act of 1970
Federal Crime Labs in the U.S.

U.S. Postal Inspection Services
Housed under The Department of Justice
 Responsibilities:

 Investigates
service
criminal acts relating to the postal
State Crime Labs in the U.S.
Most states have crime labs to assist local
law enforcement agencies that do not
have easy access to a crime lab
State Crime Labs in the U.S.
Some states, such as Alabama, have
developed a comprehensive statewide
system of crime labs with satellite facilities
Maximizes access to lab services without
duplicating services at each site
Sharing of expertise and equipment
Services of the Crime Lab
Variation in Services
There are many different services
available in different crime labs
 Reasons:

Variations in local laws
 Different capabilities and functions of the
organization in which the lab is attached
 Budgetary and staffing limitations

Full-Service Crime Lab: 5 Parts

Physical Science Unit
Applies the principles and techniques of
chemistry, physics, and geology to
identification and comparison of crime-scene
evidence
 Examples:

 Drug
Chemistry Identification
 Soil/Mineral Analysis
 Physical Properties of Trace Evidence
Full-Service Crime Lab: 5 Parts

Biology Unit
Staffed with biologists and biochemists that
apply their knowledge to the identification of
biological aspects of a crime scene
 Examples:

 Identification
and DNA profiling of dried blood
stains and other bodily fluids
 Hair and fiber comparison
 Identification of plant material
Full-Service Crime Lab: 5 Parts

Firearms Unit
Responsible for the examination of firearms,
discharged bullets, cartridge cases, shotgun
shells, and ammunition of all types
 Examples:

 Examination
of ammunition casings
 Firearm or gunpowder residue
 Target length
 Toolmarks
Full-Service Crime Lab: 5 Parts

Document Examination Unit
Studies the typewriting and handwriting on
questioned documents to determine
authenticity and/or source
 Examples:

 Handwriting
identification
 Analysis of ink or paper
 Indentations
 Erasure marks
Full-Service Crime Lab: 5 Parts

Photography Unit
Used to examine and record physical
evidence
 Examples:

 Digital
imaging
 Infrared imaging
 Ultraviolet imaging
 X-ray photography
Crime Lab Optional Services

Toxicology Unit:


Latent Fingerprint Unit


Determines the presence or absence of drugs
or poisons
Processes and examines evidence for latent
fingerprints
Polygraph Unit

Administers lie detector tests to suspects
Crime Lab Optional Services

Voiceprint Analysis Unit


Analyzes tape-recorded messages or
telephoned threats
Evidence Collection Unit

Collects and preserves evidence at the crime
scene
The Functions of the
Forensic Scientist
Forensic Scientists
Must be skilled in applying the principles and
techniques of the physical and natural
sciences to the analysis of many types of
evidence that may be recovered at a crime
scene
Forensic Scientists
Must have a firm, scientific foundation and
follow specific procedures in order for
evidence to be admissible in court
Frye v. United States

Court case that established what type of
rules scientific evidence have to follow
Said that scientific procedures will only be
allowed in a court of law if the procedures
used are “generally accepted by the scientific
community”
 Helps establish the accuracy and validity of
the tests and the results easy to understand
by all scientists

“Generally Accepted Procedures”

How are “generally accepted procedures”
determined?
Expert witnesses
 Books
 Documented studies
 Case history

Daubert v. Merrell Dow
Pharmaceutical, Inc.
Court case in 1993
 Asserted that “general acceptance” is not
an absolute prerequisite for admissibility
 The judge in the case can be a
“gatekeeper” in deciding the admissibility
and reliability of scientific evidence that is
presented in a courtroom

Daubert Precedence Guidelines

Guidelines to gauge the scientific evidence
Whether or not the method has been or can
be tested
 Whether or not the method has been
published or reviewed by others in the field
 The technique’s potential rate of error
 Standards of operational procedures
 Acceptance in the general scientific
community

Kumho Tire Co. v. Carmichael
The trial judge’s “gatekeeping” rule applies
to not only scientific evidence but also to
expert testimony
Coppolino v. State
Widened the discretion of the trial judge
 New scientific tests can be used in
evidence if no other tests can be or ever
have been performed

Must have valid principles and techniques
 Give examiners the flexibility to develop new
and better methods of testing samples

What is an Expert Witness?

Expert witnesses

Have knowledge, skill, experience, training, or
education that lends itself directly to
understanding of scientific evidence
What is an Expert Witness?

Expert witnesses are “qualified” for
competence for testimony in a courtroom
by:
Degrees awarded
 Special courses
 Professional societies
 Publications
 Occupational experience

What is an Expert Witness?

Most experts do not have Forensic
Science degrees
Most have degrees in specific science
discipline
 Training and experience is also a large part of
being “qualified” as an expert witness

More about experts…

Experts are the only people who may give
testimony as opinions in court
Opinions must be based on facts and data
 Opinions must be based on reliable principles
and methods
 Opinions must apply the facts and principles
directly to the case at hand

Expert Witness Testimony
Evaluate evidence that the court lacks
expertise to do
 Express an opinion of the significance of
the findings
 May be accepted or ignored in jury
deliberations
 Experts have no absolute certainty—their
opinions come from training or experience

Opposing an Expert Witness
Weakness in background knowledge
and/or educational experience
 Inability to explain data clearly and
logically
 Suitable qualifications are subjective
 Demeanor of the expert witness in the
courtroom

Lay v. Expert Witnesses

Expert witnesses may express opinions in
the courtroom


May or may not be dismissed by the jury or
judge
Lay witnesses may only express facts in
the courtroom

Facts must be taken into account by the jury
or judge
Evidence Collection Team
Evidence Collection is Important!
Must be collected correctly and preserved
 Some labs have Evidence Collection
Teams or Crime Scene Investigators

Trained by lab staff to gather important
physical evidence at the scene
 Work in the lab to continue their exposure to
the forensic procedures
 Use proper tools and supplies for collection
and packaging of evidence

Collecting Evidence

Sometimes specialized teams aren’t
available for evidence collection

Detectives can also collect evidence
 Effective
based on training and experience
 Classroom knowledge is necessary but experience
is best
Collecting Evidence

Every officer should be trained in fieldwork

Some officers specialize in different fields
 Traffic
 Patrol
 Investigation
 Juvenile
Control
 Evidence Collection
All Officers Should Be Familiar
Classroom Lectures
 Forensic Lab Tours
 Manuals for methods of submission of
evidence to the lab

Appendix I of your book explains some
evidence collection and packaging
procedures
Other Forensic Science
Services
Forensic Pathology
Field that involves the investigation of
sudden, unnatural, unexplained, or violent
deaths
 Involve the Medical Examiner or Coroner
and generally perform autopsies on
victims


Autopsy: the medical dissection and
examination of a body in order to determine
the cause of death
Forensic Pathology

Must answer the questions…
Who is the victim?
 What injuries are present?
 When did the injuries occur?
 Why and how were the injuries produced?

Forensic Pathology
Must determine the manner of death of the
victim
 Manners of death

 Natural
 Homicide
 Suicide
 Accident
 Undetermined
Determining Time of Death

Stages of Decomposition

Rigor Mortis:
 occurs
after death and results in the shortening of
muscle tissue and the stiffening of body parts in
the position they are in when death occurs
 Happens in the first 24 hours and disappears
within 36 hours
Determining Time of Death

Stages of Decomposition

Livor Mortis:
 Occurs
in the early stages of decomposition and
results when the heart stops pumping and blood
pools in the parts of the body closest to the ground
 Skin will appear dark blue or purple in these areas
 Condition appears immediately and continues for
up to 12 hours after death
 Skin will not appear discolored in areas where the
body is restricted by either clothing or an object
pressing against the body
Determining Time of Death

Stages of Decomposition:

Algor Mortis:
 Process
in which the body temperature continually
cools after death until it reaches the ambient or the
temperature of its’ surroundings
 General rule: the body will lose heat, beginning an
hour after death, at a rate of 1 to 1.5 degrees
Fahrenheit per hour until the environmental
temperature is reached
 Influenced by weather/clothing conditions
Determining Time of Death

Potassium levels in the ocular fluid
After death, cells release potassium into the
liquid behind the eye
 By analyzing the amount of potassium
present at various intervals after death, the
rate of potassium release can be determined
 Can help the pathologist to approximate the
time of death

Forensic Anthropology
Identification and examination of skeletal
remains
 May reveal personal attributes such as
origin, sex, age, race, and/or injury
 Facial reconstruction
 May be able to identify mass victims of
disaster through skeletal remains

Forensic Entomology
The study of insects and their relation to a
criminal investigation
 As decomposition occurs, insects arrive on
the carcass in a regular time interval
 May help determine time of death
 Results may be effected by geographical
location, climate, and weather conditions

Forensic Psychiatry
Area in which the relationship between
human behavior and legal proceedings are
examined
 Civil cases: competency to make
decisions
 Criminal cases: competency to stand trial
 Profilers: track the behavior of criminals
based on patterns and types of crimes

Forensic Engineering
Concerned with failure analysis, accident
reconstruction, and causes and origins of
fires or explosions
 Focus mainly on the logical sequence and
main cause of an accident or crime
 Also attempts to determine who or what is
responsible for the cause of an accident or
crime

Forensic Odontology
Provide information about the identification
of victims when the body is left in an
unrecognizable state
 Dental records

Characteristics of teeth
 Teeth alignment
 Overall structure of the mouth


Bite mark analysis in assault cases