Transcript Introduction to Forensic Science

Chapter 1 - Notes
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A. What is Science?
 A. Derived from the Latin verb meaning “to
Know”
 B. Science is a way of knowing
 C. A systematic acquisition of knowledge that can
be measured precisely
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“If they don’t depend on true evidence,
scientists are no better than gossips”
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- Penelope Fiztgerald (British author)
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A. Discovery science = verifiable
observations and measurements
 1. often discover by accident
 2. often give rise to inductive conclusions
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B. Example-
 1. Fleming, 1928, accidentally discovered that
fungi produce chemicals that kill bacteria. This led
to the discovery of Penicillin
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1. Inductive conclusion = a generalization
that summarizes many concurrent
observations
 1. Goes from specific observations to a
generalization
 2. Example: “all living things are made up of
cells” arose from 2 centuries of biologists
discovering cells in all biological specimens
observed
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A. As a result of asking questions and seeking
explanations
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B. Is a formal process of inquiry, consisting of
a series of steps
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C. Hypothetico-deductive reasoning is used
to answer the questions
 1. hypothesis = educated guess
 2. deductive = flows from the general to the
specific instead of specific to general
 3. usually takes the place of predictions about
outcomes of experiments or observations
 4. is “If . . . Then” logic
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1. Observation : My flashlight doesn’t work
2. Question : What’s wrong with my
flashlight?
3. Hypothesis: The flashlight’s batteries are
dead
4. Prediction : If this hypothesis is correct
5. Experiment: and I replace the batteries
with new ones
6. Predicted Result: then the flashlight
should work
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E. If the result supports the hypothesis, make
additional predictions and test them
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F. If the result does not support hypothesis,
revise hypothesis or pose new one
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A. Forensic = (adj.) Pertaining to legal
proceedings or public debate
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B. Forensic Science = application of science
to the processes of law and involves the
collection, examination, evaluation, and
interpretation of evidence
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1. Biological
2. Physical
3. Chemical
4. Medical
5. Behavioral Science
6. . . . To questions of evidence of law
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A. Early History
 A. BCE – Evidence of fingerprints in early painting
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and rock carvings
B. 700s – Chinese used fingerprints to establish
identity
C. Ca. 1000 – His DuanYu
D. 1609 – Systematic document examination
E. 1784 – First documented use of physical
matching
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A. First recorded use of questioned
document analysis
B. The development of tests for the presence
of blood in a forensic context
C. A bullet comparison used to catch a
murderer
D. The first use of toxicology in a jury trial
E. The development of the first crystal test
for hemoglobin
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F. The development of a presumptive test for
blood
G. First use of photography for the
identification of criminals and documentation
of evidence and crime scenes
H. First recorded use of fingerprints to solve
a crime
I. Development of first microscope with a
comparison bridge
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A. Establishment of popular practice of using
the comparison microscope for bullet
comparison
B. Development of ABO blood typing
technique
C. Invention of first interference contrast
microscope
D. Development of luminal
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E. Study of voiceprint identification
F. Invention of Breathalyzer
G. Use of heated headspace sampling
technique for collecting arson evidence
H. Development of scanning electron
microscope
I. Identification of polymorphic nature of red
blood cells
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J. Enactment of Federal Rules of Evidence
K. Evaluation of gas chromatograph and mas
spectrometer
L. Development of PCR technique
M. DNA profiling test
N. DNA introduced in criminal courts
O. Daubert et al. v. Merrell Dow
P. DNA database
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A. Mathieu Orfila (1787-1853) – considered
the “father” of forensic toxicology
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B. Alphonse Bertillon (1853-1914) –
developed first system of personal
identification
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C. Francis Galton (1822-1911) – developed
methodology for fingerprinting
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D. Leone Lattes (1887-1954) – developed
techniques to ID ABO blood groups
E. Calvin Goddard (1891-1944) – expert in
ballistic analysis
F. Albert Osborn (1858-1946) – document
examination
G. Walter McCrone (1916-2002) –
instrumental in using and perfecting
microscope use in forensic analysis
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H. Hans Gross (1847-1915) – application of
scientific disciplines to field of criminal
investigation
I. Edmond Locard (1877-1966) – Locard
Exchange Principle = “The exchange of
materials between 2 objects that occurs
whenever 2 objects come into contact with
one another”
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A. At present there are
about 320 crime labs
in the US
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B. This growth has
led to the advent
of DNA profiling
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A. FBI – Federal Bureau of Investigation
 i. Biggest in Justice Department, limited to 200
crimes, training, lab support
B DEA - Drug Enforcement Agency
i. Best at strategy, surveillance, joint ops
C USMS – United States Marshall Service
i. Provide security and transport for whole
system
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D. INS – Immigration and Naturalization
Service
 i. Less detective than others, are apprehension
specialists
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E. ATF – Bureau of Alcohol, Tobacco and
Firearms
 i. Treasury counterpart to FBI
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F. IRS – Internal Revenue Service
 i. Tax related, anything with underground
economy
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G. USCS – United States Customs Service
 i. Large import/export, contraband, porno duties
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H. USSS – United States Secret Service
 i. Secret service, VIP protection, counterfeiting
and fraud
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A. Function to train police investigators as to
what constitutes physical evidence and how it
should be collected, preserved, etc.
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B. Analyze this evidence
I. Physical Science Unit – chemistry, physics, and
geology; sometimes drug ID, soil and mineral
analysis and examination of trace evidence
 II. Biology Unit – DNA, blood, hairs, fibers and
botanicals
 III. Firearms Unit – ballistics and tools
 IV. Documents Unit – handwriting and
typewriting
 V. Photography Unit – document scenes and
analysis
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Toxicology
Latent Fingerprints
Polygraph
Voiceprint Analysis
Evidence Collection
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i. Pathology – medical dissection and
examination of a body in order to determine
the cause of death
 1. Autopsy – performed to establish the cause and
manner of death
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A. Natural
B. Homicide
C. Suicide
D. Accidental
E. Undetermined
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A. Rigor mortis – the medical condition that
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
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B. Livor mortis – The medical condition that
occurs after death and results in the settling
of blood in areas of the body closest to the
ground
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C. Algor mortis – Postmorten changes that
cause a body to lose heat
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Anthropology –
age, sex, race, etc.
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Entomology –
insects to
determine time
of death
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Psychiatry
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Odontology –
dental records
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Engineering
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A. Chain of Custody – three sources of error
 i. Evidence has to be discovered
 ii. It has to be collected
 iii. It has to be transported to the lab where it is
logged in, assigned an identification number,
placed in storage, and kept from mingling with
other evidence
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B. Labs must be free of contaminants
C. Tests must be performed properly and
documented
D. Evidence transported back into storage
E. Reports written on analysis of evidence
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A. Quality control manual
B. Quality assurance manual
C. Lab testing protocol
D. Program for proficiency testing – workers
up to standards
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A. Tampering
B. Contamination
C. Substitution (mistakes)
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A. Analysis of Physical Evidence
 a. Must be aware of demands and constraints
imposed by judicial system
 b. Evidence/Science must be admissible in court
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i. Court must decide if procedure, technique
or principles are “generally accepted” by a
meaningful segment of relevant scientific
community
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d. Federal Rules of Evidence – more flexible
standards for evidence
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i. Frye standard is not an absolute prerequisite to admissibility of evidence
ii. Guidelines
 1. can technique/theory be (been) tested
 2. has technique/theory been subject to peer
review and publication
 3. techniques potential rate of error
 4. existence and maintenance of standards
 5. has theory/method attracted acceptance
within relevant scientific community
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A. Expert Witness = an individual whom the
court determines possess knowledge relevant
to the trial that is not expected of the average
layperson
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C. Furnishing Training in the Proper
Recognition, Collection, and Preservation of
Physical Evidence