Transcript individualization

Forensic Science
Authentic
Professional
Science and Law
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Forensic Science - in its
broadest definition is the
application of science to
law
As our society grows more
complex, it has become
more dependent on laws to
regulate the activities of its
members.
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Forensic science
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1-Offers the knowledge and technology of
science for the definition and enforcement
of laws.
2-It cannot offer final and authoritative
solutions, however, Forensic Science does
play an important and unique roll in the
criminal justice system.
3-It uses the scientist's ability to supply
accurate and objective information that
reflects the events of a crime
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Assignment:
Careers in Forensics
* Due Wednesday August
th
* Choose your format of delivery
*
Each person will have their own
career of choice 
* Duration: 3 -4 minutes
(NO PowerPoints or Posters)
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The major areas of
forensic science
explained
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Forensic Medicine
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The application of medicine and
medical science to legal problems.
Practitioners of forensic medicine
are doctors of medicine with
special certification in pathology
and forensic pathology.
Most of them are Medical
Examiners.
They are concerned with
determining cause and
circumstances in cases of
questioned death.
They also can be involved in
matters of insurance claims, and
sometimes cases of malpractice
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Forensic Odontology
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Commonly called Forensic
Dentistry
The application of dentistry to
human identification problems.
Forensic odontolgists are dentists
who specialize in the forensic
aspect of their field.
They are concerned with the
identification of persons based
upon their dentition, usually in
cases of otherwise unrecognizable
bodies or in mass disasters.
They also analyze and compare
bite mark evidence.
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Forensic Anthropology
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Personal identification based on
bodily remains (particularly skeletal)
Practitioners are anthropologists
who are interested in Forensic
Science.
Other areas of forensic anthropology
include
 Maintaining data bases on bodily
structures as functions of race,
sex, age, stature, and so forth.
 Facial reconstruction
 Interpretation of footprint or
shoe-print evidence
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Forensic toxicology
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The determination of
toxic substances in
human tissues and
organs.
Much of the work
concerns the role toxic
agents may have played in
causing or contributing to
the death of a person.
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Trace Evidence Analysis
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Includes all areas of trace and
transfer evidence such as
 soil and glass
 hair and fibers
 blood
 physiological fluids
 arson accelerant and
explosive residues
 drug identification
 different patterns and
imprints
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Questioned Documents
Examination
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The comparison and
interpretation of ...
 handwriting
 mechanically produced
material (typing, printing)
 photocopied material
The analysis of paper, inks,
and other materials used to
produce documents
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Firearm and Toolmark
Examination
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Firearm identification
Comparison of markings on
bullets, cartridge cases, and
shell cases.
Determining if a bullet has
been fired from a particular
weapon.
Toolmark examinations are
concerned with the association
of a particular impression with
a particular tool.
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Fingerprint Examinations
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Classification of
fingerprints
Maintaining fingerprint
databases
Development and lifting of
latent prints
Comparisons of known
and unknown fingerprints
to determine a match
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The work of a Forensic
Scientist
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The Goals of a Forensic Scientist
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Recognition of physical evidence
Identification of physical evidence
Individualization of physical evidence
Evaluation of physical evidence
Reconstruction of the crime
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RECOGNITION
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Although it may seem obvious
it is important to be able to
recognize what is and is not
physical evidence
Almost anything can be physical evidence and
it is very dependant on the type of crime
committed
With practice and experience evidence
recognition becomes easier
Beware…submitting too much evidence is just
as bad as submitting too little
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IDENTIFICATION
Identification of physical evidence may be regarded
as a classification scheme
Evidence is assigned into categories containing like
items.
Initial categories are broad and then narrowed down
as more information is obtained
Example
 Blue substance
 Blue paint
 Blue car paint
 Blue car paint from Ford Manufacturing
Company
 Blue car paint from Ford produced 1998-2000
 Blue car paint from Ford produced 1998-2000,
used on Mustang and Explorer
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Class Evidence
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To identify an object in Forensic Science is really
to separate it by class
Class characteristics are the properties that all the
members of a certain group of objects or
substances have in common.
The previous “paint” example was a refined class
evidence identification
The “paint” was identified by comparing its class
characteristics with those of known standards or
previously established criteria.
The “paint” is considered CLASS EVIDENCE
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Class Evidence Examples
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Single layered paint
Soil
Glass fragments too small to fit back
together
Hairs
Fibers
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The Value of Class Evidence
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Many lawyers try to discredit class evidence
because it cannot be limited to just one possible
source
However Class Evidence DOES HAVE VALUE.
Look around room, most have different clothes on.
If I were to pick a fiber from one persons clothes in
this room, that fiber could possibly pick out the
single source or at least narrow the field
Some class evidence holds little forensic value such
as fiber from jeans or white cotton shirts…they are
too common
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Individualization
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Individualization is unique to Forensic
Science
It refers to the demonstration that a
particular sample is unique, even among
members of the same class.
It may also refer to the demonstration that
a questioned piece of physical evidence
and a similar known sample have a
common origin.
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More Than CLASS
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In addition to class characteristics, objects and
materials possess individual characteristics that
can be used to distinguish members of the same
class.
The nature of these individual characteristics
varies from one type of evidence to another, but
forensic scientists try to take advantage of them
in effort to individualize a piece of physical
evidence by some type of comparison process.
Only a few types of physical evidence (primarily
physical pattern evidence) can be truly
individualized
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Evidence that contain
Individualizing Characteristics
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Fingerprints
Handwriting
Bullets
Toolmarks
Shoeprints
Tire prints
Glass fragments that can be matched
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Problems with Words
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Identification is sometimes used to mean
personal identification
Fingerprints for example, can be used to
“identify” an individual
The terminology is unfortunate, since this
process is really “individualization”
Likewise, dental evidence and dental
records are used in “identifying” dead
bodies...when they are really
individualizing
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The GOAL...
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Ultimate goal would be to move all class
evidence to individualistic which is not very
likely
Hair is trying to make the move...something like
paint probably never will.
For human evidence to be individualistic, the
odds of two people matching the same piece of
evidence must be 1 in about 7.5 billion, which is
the population of the earth.
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Is DNA Individualistic??
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Up to the late 1990’s, the smallest odds
were 1 in 100 million. This narrowed it to 1
in 50 people on the earth, but it still was
not individualistic.
More recently with new DNA techniques,
the new odds are proving to be
“individualistic”
However we still have the problem of
identical twins having the same DNA
(but they do have different fingerprints!)
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Reconstruction
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Reconstruction refers to
the process of putting the
“pieces” of a case or
situation together
The objective is to reach an understanding of
a sequence of past events based on the record
of physical evidence
Identification and individualization of
physical evidence plays a crucial role in
providing data for reconstructions
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