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Forensic Science
An Introduction
“I want to be a CSI.”
• It’s cool, glamorous and fun. You can drive
humvees, carry a gun, wear expensive clothes and
earn lots of money!
CSI shows give 'unrealistic view'
By Paul Rincon
BBC News science reporter
The CSI Effect
Reference to the phenomenon which raises real world expectations
of forensic science and crime scene investigation by general public,
victims of crime, jury members and even criminals.
'CSI effect' has juries wanting
more evidence
By Richard Willing, USA TODAY
Understanding the CSI Effect
• Glamorizing the field of forensic science.
• Overstating the accuracy of forensic techniques.
• Exaggerating the abilities of forensic science.
• Inaccurate time frame on when cases get solved.
• Many prosecutors, judges and journalists have claimed
that watching television programs such as CSI: has caused
jurors to wrongfully acquit guilty defendants when the
prosecution presents no scientific evidence in support of
the case
Forensic Science
“The application of science to the
criminal and civic laws that are
enforced by police agencies in a
criminal justice system.”
An umbrella term encompassing a
myriad of professions that use their
skills to help law enforcement
officials conduct their investigations.
How and Why is Science
Important to Law?
As our society has grown more
complex, it has become more
dependent on rules of law to
regulate the activities of its
members
Science has become a potent
tool in the enforcement of
civil and criminal law.
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Food & Drugs
Automobile Emissions
Purity of water
Levels of toxins
Forensic
Science
The diversity of
professions
practicing forensic
science is
illustrated by the
eleven sections of
The American
Academy of
Forensic Science.
• Criminalistics
• Digital & Multimedia
Sciences
• Engineering Sciences
• General
• Jurisprudence
• Odontology
• Pathology/Biology
• Physical Anthropology
• Psychiatry/Behavioral
Sciences
• Questioned Documents
• Toxicology
History of Forensic Science
Sir Arthur Conan
Doyle’s legendary
detective Sherlock
Holmes applied many
of the principles of
modern forensic
science long before
they were adopted
widely by police.
History of Forensic Science
Mathieu Orfila (1787 – 1853):
Toxicology
Alphonse Bertillon (1853 – 1914):
Anthropometry
History of Forensic Science
• Francis Galton (1822 – 1911): Fingerprints
• Hans Gross (1847 – 1915): Criminal
Investigation
• Leone Lattes (1887 – 1954): Bloodtypes
• Calvin Goddard (1891 – 1955): Comparison
Microscope
• Albert S. Osborn (1858 – 1946): Document
Examination
• Walter C. McCrone (1916 – 2002): Microscopy
 Edmond Locard (1877 – 1966): Scientific
Method (Locards Exchange Principle)
Locard Exchange Principle
"Everywhere you go,
you take something
with you, and you leave
something behind."
Locard Exchange Principle
Anytime there is contact
between two surfaces,
there will be a mutual
exchange of matter
across the contact
boundary
Locard Exchange Principle
'Wherever he steps, whatever he touches, whatever he
leaves, even unconsciously, will serve as a silent witness
against him. Not only his fingerprints or his footprints,
but his hair, the fibers from his clothes, the glass he
breaks, the tool mark he leaves, the paint he scratches,
the blood or semen he deposits or collects. All of these
and more, bear mute witness against him. This is
evidence that does not forget. It is not confused by the
excitement of the moment. It is not absent because
human witnesses are. It is factual evidence. Physical
evidence cannot be wrong, it cannot perjure itself, it
cannot be wholly absent. Only human failure to find it,
study and understand it, can diminish its value. ‘
-Professor Edmond Locard
1932
The Federal Bureau of
Investigation (FBI) crime
laboratory is created.
The Growth of Crime Laboratories
At present, nearly 400 public crime laboratories
operate at various levels of government (federal,
state, county and municipal) – more than three times
the number of crime laboratories operating in 1966.
•Supreme court decisions in the 1960’s were responsible for
greater police emphasis on securing scientifically evaluated
evidence.
•Increase in crime rates in the last 40 years.
All illicit-drug seizures must be sent to a forensic laboratory
for confirmatory chemical analysis before the case can be
adjudicated.
The advent of DNA profiling
Services of the Crime Laboratory
Five Basic Units
1. Physical Science Unit
2. Biology Unit
3. Firearms Unit
4. Document Examination Unit
5. Photography Unit
Optional Services
•Toxicology Unit
•Latent Fingerprint Unit
•Polygraph Unit
•Voiceprint Analysis Unit
•Crime Scene Investigation
Unit
Physical Science Unit
Applies principles and techniques of
chemistry, physics, and geology to the
identification and comparison of crime-scene
evidence.
•Uses chemical tests and analytical
instrumentation to examine items such as:
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Drugs
Glass
Paint
Explosives
Soil
Biology Unit
Identification and DNA
profiling of:
– dried bloodstains
– other bodily fluids
– hairs
– fibers
– botanical materials
Firearms Unit
Examines:
– firearms
– discharged bullets
– cartridge cases
– shotgun shells
– ammunition of all
types
– residue on clothing
and other objects
Documentation Examination Unit
• Studies handwriting and typewriting on
questioned documents to determine
authenticity and source.
• Analyze paper and ink
• Indented writings
• Erasures
• Obliterations
• Burned or charred documents
Photography Unit
• Examines and records physical
evidence
• The following may be required
to make invisible information
visible:
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Digital imaging
Infrared
Ultraviolet light
X-ray photography
• Also aids in the preparation of
photographic exhibits for
courtroom presentation.
Toxicology Unit
Examine body fluids and
organs to determine
presence or absence of
drugs or poisons
Latent Fingerprint Unit
• Processes and examines evidence for
latent (not visible to the naked eye)
fingerprints – dactyloscopy
Polygraph Unit
• Tool for criminal investigator, not forensic
scientist
• Handled by people trained in techniques of
criminal investigation and interrogation
Voiceprint Analysis Unit
• Used in cases involving telephone threats or
tape-recorded messages
• Use a sound spectrograph (an instrument
that transforms speech into a visual graphic
display called a voiceprint)
Crime-Scene Investigation Unit
Specially trained personnel dispatched to
crime scene (civilian or police) to collect
and preserve physical evidence that will
later be processed at the crime
laboratory.
Other Forensic Services
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Forensic Psychiatry
Forensic Odontology
Forensic Engineering
Forensic Computer
and Digital Analysis
Forensic Psychiatry
Examines the relationship between human
behavior and legal proceedings
Forensic Odontology
• The study of teeth as it
relates to the law.
• Provides information for
identification of victim
• Characteristics of
Teeth
– overall mouth structure
– alignment of teeth
– bite mark analysis
Forensic Engineering
Engineers are concerned
with failure analysis,
accident reconstruction,
causes and origins of
fires and explosions
Forensic Computer and Digital Analysis
• New and fastgrowing field
• Identification,
collection,
preservation, and
examination of
information derived
from computers and
other digital devices
Functions of Forensic Scientist
1) Proper Recognition, Collection,
and Preservation of Physical
Evidence
2) Analysis of Physical Evidence
3) Expert Testimony
What do you see?
How about now?