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Chapter 1
Introduction to Forensic Science
Definition and Scope
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Forensic science is the application of
science to law
Applies the knowledge and technology of
science for the definition and enforcement
of laws
Supplies accurate and objective
information that reflects the events that
have occurred at the crime
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The terms
“Criminalistics” and
“Forensic Science”
can be used
interchangeably.
History
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Mathieu Orfila –
father of
toxicology; formed
treatise on the
detection of
poisons and their
effects on animals
(1814)
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Alphonse Bertillon –
first system of
personal identification
called anthropometry
– a procedure of
taking s series of body
measurement as a
means of
distinguishing one
individual from
another (1879)
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Francis Galton – first definitive study of
fingerprints and developed methodology of
classifying them for filing; published Finger
Prints in 1892
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Leone Lattes – in 1915, he devised a
simple procedure for determining blood
group of dried bloodstain
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Calvin Goddard (1891-1955)– used a
comparison microscope to analyze bullets;
requires a comparison of the crime scene
bullet to one test-fired from the suspect’s
gun
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Hans Gross (1847-1915) – wrote a book
outlining the principles of criminal
investigation; he detailed the assistance
investigators could expect from
microscopy, chemistry, physics,
mineralogy, botany, zoology,
anthropometry, and fingerprinting
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Edmond Locard – persuaded police
department in France to give him two attics
rooms and two assistants to create a crime
lab; founder and director of the Institute of
Criminalistics in France; his success
sparked the creation of crime labs Vienna,
Berlin, Sweden, Finland, and Holland
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Locard’s Exchange Principle – the
exchange of materials between two objects
that occurs whenever two objects come
into contact with each other
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Locard believed that every criminal can be
connected to a crime by dust particles carried
from the crime scene
History of Forensic Science
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1923 – LAPD creates first crime lab in US
1932 – FBI organized a national crime lab
to offer services to law enforcement
agencies in the country; currently, the
world’s largest forensic lab
Organization/History of a Crime Lab
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Rapid Growth –
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Necessity of police to secure scientifically
evaluated evidence
Increasing crime rate
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Drug related crimes
DNA profiling
Organization/History of a Crime Lab
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Federal Crime Labs
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FBI (Department of Justice)
Drug Enforcement Administration (Department of
Justice)
Bureau of Alcohol, Tobacco, Firearms, and
Explosives (Department of Justice)
U.S. Postal Inspection Service
State Crime Labs
Local Crime Labs (municipals/counties)
Service of the Crime Lab
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Individual crime labs
vary in the type of
service it provides based
on:
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Variations in local law
Different capacities and
functions of the
organization to attached to
the crime unit
Budgetary/staffing
limitations
Service of the Crime Lab
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Physical Science Unit
Biology Unit
Firearms Unit
Document Examination Unit
Photography Unit
Toxicology Unit
Latent Fingerprint Unit
Polygraph Unit
Voice Analysis Unit
Evidence-Collection Unit
Functions of Forensic Scientist
1.
2.
3.
Collection of Physical Evidence
Analysis of Physical Evidence
Provision of Expert Testimony
Functions of Forensic Scientist
1.
Collection of Physical Evidence
Forensic Science begins at the crime scene. If the
investigator cannot recognize physical evidence or
cannot properly preserve it for laboratory examination,
no amount of sophisticated laboratory instrumentation or
technical expertise can salvage the situation.
Physical Evidence can achieve its optimum value in criminal
investigations only when its collection is performed with
a selectivity governed by the collector’s thorough
knowledge of the crime lab’s techniques, capabilities,
and limitations
Functions of Forensic Scientist
2. Analysis of Physical Evidence
A forensic scientist must be skilled in
applying the principles and techniques of
the physical and natural sciences to the
analysis of the many types of evidence
that may be recovered during a criminal
investigations.
Functions of Forensic Scientist
3.
Provision of Expert Testimony
The forensic scientist must also be aware of the
demands and constraints that are imposed by
the judicial system. The procedures and
techniques that are used in the laboratory must
not only rest on a firm scientific foundation but
also satisfy the criteria of admissibility that have
been established by the courts.
Court Cases
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Frye v. US
Federal Rules of Evidence
Daubert v. Merrell Dow Pharmaceutical, Inc
Kumho Tire co v. Carmichael
Coppolino v. State
Frye v. US
(1923)
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Set guidelines for determining the
admissibility of scientific evidence.
Evidence in question must be “generally
accepted” by the scientific community.
Federal Rules of Evidence
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Governs the admissibility of all evidence,
including expert testimony, in federal courts
Many states adopted codes similar to this
“A witness qualified as an expert by knowledge,
skill, experience, training, or education, may
testify….if (1) the testimony is based on sufficient
facts or data, (2) the testimony is the product of
reliable principles and methods, and (3) the
witness has applied the principles and methods
reliably to the facts of the case.”
Daubert v. Merrell Dow Pharmaceutical,
Inc. (1993)
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Stated that Frye v. US needed to allow for the
courts to make the final judgement on
admissibility and validity
Judge must assume responsibility in determining
the admissibility and reliability of scientific
evidence
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Theory must be (has been) tested
Subject to peer review or publication
Rate of error
Standards of technique
Widespread acceptance
Kumho Tire co v. Carmichael(1999)
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The “gatekeeping” role of the trial judge
applied not only to scientific testimony but
to all expert testimony
Coppolino v. State
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Techniques that make new discoveries are
still admissible
Provision of Expert Testimony
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Expert witness – an individual whom the
court determines possesses knowledge
relevant to the trial is not expected of the
average layperson
Other Forensic Science Services
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Forensic Pathology
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The investigation of sudden, unnatural, unexplained,
or violent deaths.
Typically performed by coroners or medical
examiners
Primary role is to determine the cause of death; if the
cause cannot be found through observation, an
autopsy is performed
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Cause of death can be classified into five categories:
natural, homicide, suicide, accident, or undetermined
Other Forensic Science Services
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Forensic Pathology
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A medical examiner can often estimate the time of death by evaluating
the stage of decomposition:
Rigor mortis- immediately following death, when the body relaxes and
then becomes rigid without the shortening of the muscles. Usually
occurs within the first 24 hours and disappears within 36 hours.
Livor mortis – when the human heart stops pumping and the blood
begins to settle in the parts of the body closest to the ground. The skin
will appear as dark blue or purple in theses areas. Begins immediately
after death and continues for up to 12 hours
Algor mortis – process whereby the body temperature continually
cools after death until it reaches room temperature; depending on the
environmental conditions, beginning about an hour after death, the
body will lose heat at a rate of 1-1.5 degrees Fahrenheit per hour
Other Forensic Science Services
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Forensic Pathology
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Algor mortis – process whereby the body temperature
continually cools after death until it reaches room temperature;
depending on the environmental conditions, beginning about an
hour after death, the body will lose heat at a rate of 1-1.5
degrees Fahrenheit per hour
Potassium levels in ocular fluid (vitreous humor) – after
death, cells within the inner surface of the eyeball release
potassium into the vitreous humor. By analyzing the amount of
potassium present at various intervals after death, the rate at
which potassium is released can be determined. This rate can
be used to approximate the time of death.
Other Forensic Science Services
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Forensic Anthropology
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The identification and examination of human skeleton
remains
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Bones undergo an extremely slow breakdown process
Can provide several types of individual characteristics:
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Origin
Sex
Approximate age
Race
Skeletal injury
Facial reconstructions
Useful in identifying victims of mass disasters
Other Forensic Science Services
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Forensic Entomology
 The study of insects and their relation to a criminal
investigation
 Used to estimate time of death
 Insects will infect body once decomposition begins
and lay eggs; the entomologist can identify the
specific insects present in the body and approximate
how long a body has been left exposed by
examining the stage of development of the larvae
Other Forensic Science Services
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Forensic Psychiatry
 The relationship between human behavior and legal
proceedings is examined.
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Civil cases – determine whether people are competent to
make decisions about preparing wills, settling property, or
refusing medical treatment
Criminal cases – evaluate behavioral disorders and
determine whether people are competent to stand trial
Also examine behavioral patterns of criminals to help
develop a criminal’s behavioral profile
Other Forensic Science Services
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Forensic Odontology
 Identification through dental records
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Because of teeth enamel’s resilience, the teeth will
outlast tissues and organs as decomposition begins
Characteristics of teeth, their alignment, and the
overall structure of the mouth provide evidence for
identifying a specific person
Bite marks on a victim can be analyzed and compared
to suspect
Other Forensic Science Services
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Forensic Engineering
 Concerns itself with accident reconstruction and
causes and origins of fires and explosions