Transcript Introduction to Forensic Science and the Law

Chapters 1 and 2
Introduction
to Forensic Science and Crime
Scene Investigation
“In school, every period ends with a bell.
Every sentence ends with a period.
Every crime ends with a sentence.”
—Stephen Wright, comedian
Forensic Science
 The study and application of science
to matters of law.
 “Forensis” meaning forum
 Public place where, in Roman times,
senators and others debated and held
judicial proceedings
Criminalistics vs Criminology
Criminalistics
Criminology
 the scientific
examination of
physical evidence for
legal purposes.
 includes the
psychological angle,
studying the crime
scene for motive,
traits, and behavior
that will help to
interpret the evidence
Crime Lab—Basic Services
 Physical Science Unit
 Chemistry
 Physics
 Geology
 Biology Unit
 Firearms Unit
 Document Examination
Unit
 Photography Unit
Crime Lab—Optional Services
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Toxicology Unit
Latent Fingerprint Unit
Polygraph Unit
Voiceprint Analysis Unit
Evidence Collection Unit
Other Forensic Science Services
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Forensic Pathology
Forensic Anthropology
Forensic Entomology
Forensic Psychiatry
Forensic Odontology
Forensic Engineering
Cybertechnology
Major Crime Laboratories
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FBI
DEA
ATF
U.S. Postal Service
U.S. Fish and Wildlife Service
Crime Lab History
First police crime lab in the world
 France in 1910 by Edmond Locard
First police crime lab in the U.S.
 1923 in Los Angeles
The Scientific Crime Detection Lab
 Evanston, Illinois in 1929
The first FBI crime lab opened in 1932
Major Developments
in Forensic Science History
 700s AD—Chinese used fingerprints to establish identity
of documents and clay sculptures
 ~1000—Roman courts determined that bloody palm prints
were used to frame a man in his brother’s murder
 1149—King Richard of England introduced the idea of the
coroner to investigate questionable death
 1200s—A murder in China is solved when flies were
attracted to invisible blood residue on a sword of a man
in the community
 1670—Anton Van Leeuwenhoek constructed the first highpowered microscope
 1776—Paul Revere identified the body of General Joseph
Warren based on the false teeth he had made for him
 1784—John Toms convicted of murder on basis of torn
edge of wad of paper in pistol matching a piece of paper in
his pocket
Major Developments in Forensic Science
History
 1859—Gustav Kirchhoff and Robert Bunsen developed the science of
spectroscopy.
 1864—Crime scene photography developed
 1879—Alphonse Bertillon developed a system to identify people using
particular body measurements
 1896—Edward Henry developed first classification system for
fingerprint identification
 1900—Karl Landsteiner identified human blood groups
 1904—Edmond Locard formulated his famous principle, “Every
contact leaves a trace.”
 1922—Francis Aston developed the mass spectrometer.
 1959—James Watson and Francis Crick discover the DNA double
helix
 1977—AFIS developed by FBI, fully automated in 1996
 1984—Jeffreys developed and used first DNA tests to be applied to a
criminal case
People of Historical Significance
Edmond Locard (1877-1966)
 French professor
 Considered the father of
criminalistics
 Built the world’s first forensic
laboratory in France in 1910
 Locard Exchange Principle
 Whenever two objects come into
contact with each other, traces of
each are exchanged.
Crime Scene Team
 A group of professional investigators, each trained in a variety
of special disciplines.
 Team Members
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First Police Officer on the scene
Medics (if necessary)
Investigator(s)
Medical Examiner or Representative (if necessary)
Photographer and/or Field Evidence Technician
Lab Experts
pathologist
serologist
DNA expert
toxicologist
forensic odontologist
forensic anthropologist
forensic psychologist
forensic entomologist
firearm examiner
bomb and arson expert
document and handwriting experts
fingerprint expert
Scientific Method
(as it pertains to criminalistics)
1. Observe a problem or questioned evidence
and collect objective data.
2. Consider a hypothesis or possible solution.
3. Examine, test, and then analyze the
evidence.
4. Determine the significance of the evidence.
5. Formulate a theory based on evaluation of
the significance of the evidence.
Complex Reasoning Skills
Necessary to Work Through and Solve Crimes:
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Deductive and Inductive Reasoning
Classifying
Comparing and Contrasting
Problem Solving
Analyzing Perspectives
Constructing Support
Error Analysis
Laws that Pertain to the
U.S. Criminal Justice System
 The U.S. Constitution
 Statutory Law
 Common Law or Case
Law
 Civil Law
 Criminal Law
 Equity Law
 Administrative Law
The Bill of Rights
Gives individuals the right:
 To be presumed innocent until
proven guilty
 Not to be searched
unreasonably
 Not to be arrested without
probable cause
 Against unreasonable seizure
of personal property
 Against self-incrimination
 To fair questioning by police
 To protection from physical
harm throughout the justice
process
 To an attorney
 To trial by jury
 To know any charges against
oneself
 To cross-examine prosecution
witnesses
 To speak and present
witnesses
 Not to be tried again for the
same crime
 Against cruel and unusual
punishment
 To due process
 To a speedy trial
 Against excessive bail
 Against excessive fines
 To be treated the same as
others, regardless of race,
gender, religious preference,
country of origin, and other
personal attributes
Miranda v Arizona
 In 1963, Ernesto Miranda, a 23 year old mentally
disturbed man, was accused of kidnapping and raping
an 18-year-old woman in Phoenix, Arizona. He was
brought in for questioning, and confessed to the crime.
He was not told that he did not have to speak or that he
could have a lawyer present. At trial, Miranda's lawyer
tried to get the confession thrown out, but the motion
was denied. The case went to the Supreme Court in
1966. The Court ruled that the statements made to the
police could not be used as evidence, since Mr. Miranda
had not been advised of his rights.
Miranda Rights
The following is a minimal Miranda
warning:
 You have the right to remain silent. Anything
you say can and will be used against you in a
court of law. You have the right to speak to an
attorney, and to have an attorney present during
any questioning. If you cannot afford a lawyer,
one will be provided for you at the government’s
expense.
Types of Crimes
 Infraction
 Misdemeanor
 Felony
Federal Rules of Evidence
In order for evidence to
be admissible, it must
be:
 Probative — actually prove
something
 Material — address an issue
that is relevant to the
particular crime
Admissibility of Evidence
1923 Frye v. United
States
• Admissibility is
determined by:
• generally accepted by
the relevant scientific
community
• No guidance on reliability
• Jury decides if it can be
used.
1993 Daubert v. Dow
Admissibility is determined by:
 If theory or technique can be
tested
 If science has been offered
for peer review
 If rate of error is acceptable
 If the method at issue enjoys
widespread acceptance.
 If the opinion is relevant to
the issue
The judge decides if the
evidence can be entered
into the trial.
Facets of Guilt
Try to prove:
 Means—person had the ability to do the
crime
 Motive—person had a reason to do the
crime (not necessary to prove in a court of law)
 Opportunity—person can be placed at
the crime
“If the Law has made you a witness, remain a
man (woman) of science.
You have no victim to avenge, no guilty or
innocent person to ruin or save.
You must bear testimony within the limits of
science.”
—P.C.H. Brouardel
Types of Evidence
“You can learn a lot by just watching.”
—Yogi Berra, former New York Yankees catcher and sage
Evidence
Students will learn:
 The difference between
indirect and direct evidence
 That eyewitness accounts
have limitations
 What is meant by physical
evidence and give examples
 What physical evidence can
and cannot prove in court
 The significance of individual
and class evidence
Types of Evidence
Two general types:
 Testimonial—a statement made under oath
 Direct evidence or Prima Facie evidence
 Physical—any object or material that is relevant in a crime
 Indirect evidence
 Examples: hair, fiber, fingerprints, documents, blood, soil, drugs,
tool marks, impressions, glass.
Reliability of Eyewitness
Factors:
 Nature of the offense and the situation in which the
crime is observed
 Characteristics of the witness
 Manner in which the information is retrieved
Additional factors:
 Witness’s prior relationship with the accused
 Length of time between the offense and the
identification
 Any prior identification or failure to identify the
defendant
 Any prior identification of a person other than the
defendant by the eyewitness
Eyewitness
 A police composite may
be developed from the
witness testimony by a
computer program or
forensic artist.
 “Perception is reality.”
 As a result of the
influences in eyewitness
memory, physical
evidence becomes
critical.
Faces—a composite program
by InterQuest
Value of Physical Evidence
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Generally more reliable than testimonial
Can prove that a crime has been committed
Can corroborate or refute testimony
Can link a suspect with a victim or with a crime
scene
 Can establish the identity of persons associated
with a crime
 Can allow reconstruction of events of a crime
Reconstruction
Physical Evidence is used to answer questions about:
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what took place
how the victim was killed
number of people involved
sequence of events
A forensic scientist will compare the questioned or
unknown sample with a sample of known origin.
Types of Physical Evidence
 Transient Evidence—temporary; easily changed or lost;
usually observed by the first officer at the scene
 Pattern Evidence—produced by direct contact between a
person and an object or between two objects
 Conditional Evidence—produced by a specific event or
action; important in crime scene reconstruction and in
determining the set of circumstances or sequence within a
particular event
 Transfer Evidence—produced by contact between person(s)
or object(s), or between person(s) and person(s)
 Associative Evidence—items that may associate a victim or
suspect with a scene or each other; ie, personal belongings
—Lee and Labriola in Famous Cases, 2001
Examples of Transient Evidence
 Odor—putrefaction, perfume,
gasoline, urine, burning,
explosives, cigarette or cigar
smoke
 Temperature—surroundings, car
hood, coffee, water in a bathtub,
cadaver
 Imprints and indentations—
footprints, teeth marks in
perishable foods, tire marks on
certain surfaces
 Markings
Examples of Pattern Evidence
Pattern Evidence—most are in the form of
imprints, indentations, striations, markings,
fractures or deposits.
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Blood spatter
Glass fracture
Fire burn pattern
Furniture position
Projectile trajectory
Tire marks or skid marks
 Clothing or article
distribution
 Gun powder residue
 Material damage
 Body position
 Tool marks
 Modus operandi
Examples of Conditional Evidence
 Light—headlight, lighting
conditions
 Smoke—color, direction of
travel, density, odor
 Fire—color and direction of
the flames, speed of spread,
temperature and condition of
fire
 Location—of injuries or
wounds, of bloodstains, of
the victim’s vehicle, of
weapons or cartridge cases,
of broken glass
 Vehicles—doors locked or
unlocked, windows opened
or closed, radio off or on
(station), odometer mileage
 Body—position, types of
wounds; rigor, livor and algor
mortis
 Scene—condition of
furniture, doors and
windows, any disturbance or
signs of a struggle
Classification of
Evidence by Nature
 Biological—blood, semen, saliva, sweat, tears, hair,
bone, tissues, urine, feces, animal material, insects,
bacterial, fungal, botanical
 Chemical—fibers, glass, soil, gunpowder, metal, mineral,
narcotics, drugs, paper, ink, cosmetics, paint, plastic,
lubricants, fertilizer
 Physical—fingerprints, footprints, shoe prints,
handwriting, firearms, tire marks, tool marks, typewriting
 Miscellaneous—laundry marks, voice analysis,
polygraph, photography, stress evaluation,
psycholinguistic analysis, vehicle identification
Evidence Characteristics
 Class—common to a group of objects or persons
 Individual—can be identified with a particular
person or a single source
Fingerprints
Blood DNA Typing
Class vs Individual Evidence
Which examples
do you think
could be
individual
evidence?
Forensic Investigations
Include some or all of these seven major activities
1. Recognition—ability to distinguish important
evidence from unrelated material
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Pattern recognition
Physical property observation
Information analysis
Field testing
2. Preservation—collection and proper
preservation of evidence
Investigations
3. Identification—use of scientific testing
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Physical properties
Chemical properties
Morphological (structural) properties
Biological properties
Immunological properties
4. Comparison—class characteristics are
measured against those of known standards or
controls; if all measurements are equal, then the
two samples may be considered to have come
from the same source or origin.
Investigations:
5. Individualization—demonstrating that the sample
is unique, even among members of the same
class
6. Interpretation—gives meaning to all the
information
7. Reconstruction—reconstructs the events of the
case
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Inductive and deductive logic
Statistical data
Pattern analysis
Results of laboratory analysis
—Lee, Dr. Henry. Famous Crimes, 2001
Class vs Individual Evidence
 These fibers are class
evidence; there is no
way to determine if
they came from this
garment.
 The large piece of
glass fits exactly to the
bottle; it is individual
evidence.
People in the News
Dr. Henry Lee—Chief Emeritus for Scientific
Services and the former Commissioner of
Public Safety for the state of Connecticut. He
served as that state’s Chief Criminality from
1979 to 2000. Lee was the driving force in
establishing the modern forensic lab in
Connecticut. He has worked with many high
profile cases including O.J. Simpson, Jon
Benet Ramsey, and the “wood chipper” case.
He is also seen on many of the true crime
shows, including his own, “Trace Evidence:
The Case Files of Dr. Henry Lee”. Learn
more at his website:
www.drhenrylee.com/review.shtml
FBI Investigation
Read a case investigated by the FBI.
Observe the various units of their lab and
read the section: “How Did They Do That?”.
www.fbi.gov/kids/6th12th/investigates/investigates.htm
Chapter 2:
THE CRIME SCENE
“Oh, how simple it
would all have been
had I been here before
they came like a herd of
buffalo and wallowed all
over it.”
—A. Conan Doyle, in The Boscombe
Valley Mystery, 1892
CRIME SCENE
Students will learn:
 The steps to take when
processing a crime scene.
 The type of evidence that
determines what packaging
should be used.
 Why the chain of custody must
be preserved.
Students will be able to:
 Isolate, record, and search for
evidence at a mock crime
scene.
 Collect and package evidence
at a mock crime scene using to
proper forensic procedures.
CORPUS DELICTI
“Body of the Crime”
 You must prove
 that a crime occurred
 that the person charged with the crime was responsible for the
crime
 Source of Evidence
 Body
 Primary and/or Secondary Crime Scene
 Suspect(s)
CRIME SCENE TEAM
 A group of professional investigators, each
trained in a variety of special disciplines.
 Team Members
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First Police Officer on the scene
Medics (if necessary)
Investigator(s)
Medical Examiner (if necessary)
Photographer and/or Field Evidence Technician
Lab Experts
CRIME SCENE
INVESTIGATION
Based on the scientific method and the
Locard Exchange Principle, logic and forensic
techniques
 Involves:
 Recognition—scene survey, documentation,
collection
 Identification—comparison testing
 Individualization—evaluation and interpretation
 Reconstruction—reporting and presenting
PROCESSING A
CRIME SCENE
 Isolate and secure the
scene
 Document the scene
 Search for evidence
 Collect and package
evidence, maintaining
the chain of custody
 Submit evidence to the
crime lab
FIRST OFFICER
ON THE SCENE
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Assess the crime scene
and assist those hurt
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Detain the witness
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Arrest the perpetrator
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Protect the crime scene
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Take notes
CRIME SCENE SURVEY
Walk-through—performed by the crime scene investigator, the first officer
and sometimes the lead detective
Purpose:
 Mentally prepare a reconstruction theory
 Note any transient or conditional evidence that could change over
time.
 Note weather conditions
 Note points of entry or exit, as well as paths of travel within the crime
scene
 Record initial observations of who, what, where, when, and how
 Identify special needs within the crime scene for personnel,
precautions or equipment and notify superior officers or other
agencies
DOCUMENTATION
 Notes—date and time, description of the location, weather
and environmental conditions, description of the crime,
location of the evidence relative to other key points, the
names of all people involved, modifications that have
occurred and other relevant information
 Photography—photos of scene and surroundings, midrange to close-up photos with various angles of each
piece of evidence, photos as viewed by any witnesses.
 Sketches—inclusion of date, time, scale, reference
points, distance measurements, names of investigators,
victims, suspects, and a legend (key)
 Videography—allows narration (non-subjective) to be
included
SEARCH METHODS
 Line or strip method—best in large, outdoor scenes
 Grid method—basically a double-line search; effective,
but time-consuming
 Zone method—most effective in houses or buildings;
teams are assigned small zones for searching
 Wheel or ray method—best on small, circular crime
scenes
 Spiral method—may move inward or outward; best used
where there are no physical barriers
CRIME SCENE SKETCH
Date: August 14, 2005
Time: 11:35 am
Criminalist: Ann Wilson
Location: 4358 Rockledge Dr, St. Louis, Mo.
N
COLLECTING AND
PACKAGING EVIDENCE
 One individual should be designated as the evidence
collector to ensure that the evidence is collected,
packaged, marked, sealed, and preserved in a consistent
manner
 Each item must be placed in a separate container, sealed,
and labeled
 Most fragile is collected and packaged first
 Different types of evidence require specific or special
collection and packaging techniques
 The body is the property of the coroner or medical
examiner. The collection of evidence on the body is done
by that department
PACKAGING
Most items should be packaged in a
primary container and then placed
inside a secondary one. These are
then placed inside other containers
such as paper bags, plastic bags,
canisters, packets and envelopes
depending on the type and size of
the evidence.
CHAIN OF CUSTODY
There must be a written record of all people
who have had possession of an item of
evidence.
 The evidence container must be marked for
identification
 The collector’s initials should be placed on the
seal
 If evidence is turned over to another person, the
transfer must be recorded.
CRIME SCENE
RECONSTRUCTION
Stages
 Data collection
 Hypothesis formation
 Examination, testing and analysis
 Determination of the significance of
the evidence
 Theory formulation
INVESTIGATORS
“The wise forensic investigator will always remember
that he must bring all of his life experiences and logic
to find the truth. This means common sense,
informed intuition, and the courage to see things as
they are. Then he must speak honestly about what it
adds up to.”
—Dr. Henry Lee
Chief Emeritus for Scientific Services and the
former Commissioner of Public Safety for the state of Connecticut
THE MEDICAL EXAMINER
AND THE CORONER
 A medical examiner is a medical doctor,
usually a pathologist and is appointed by the
governing body of the area. There are 400
forensic pathologists throughout the U.S.
 A coroner is an elected official who usually
has no special medical training. In four
states, the coroner is a medical doctor.
MEDICAL EXAMINER’S
RESPONSIBILITIES
 Identify the deceased
 Establish the time and date of death
 Determine a medical cause of death—the injury or disease that resulted
in the person dying
 Determine the mechanism of death—the physiological reason that the
person died
 Classify the manner of death
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Natural
Accidental
Suicide
Homicide
Undetermined
 Notify the next of kin
THE CORPSE
“The way I see it, being dead is not terribly far off from
being on a cruise ship. Most of your time is spent
lying on your back. The brain has shut down. The
flesh begins to soften. Nothing much new happens,
and nothing is expected of you.”
—Mary Roach. Stiff. W. W. Norton &
Company. 2003
PEOPLE IN THE NEWS
Dr. Michael M. Baden is a renowned pathologist
and was the Chief Medical Examiner in NY City
and for Suffolk County.
Dr. Baden was on the panel that investigated the
assassinations of president John F. Kennedy
and Dr. Martin Luther King, Jr. He has been
involved as an expert in forensic pathology in
many cases of international interest including:
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The remains of Tsar Nicholas of Russia and his family
The Claus Von Bulow murder trial
Expert witness for the defense in the O.J. Simpson trial
Re-autopsy of Medgar Evers, Civil Rights leader
Re-examination of the Lindberg Kidnapping and murder
Autopsies of the victims of TWA Flight 800
Dr. Baden is the host of HBO’s Autopsy series and
is featured on many of the crime talk shows.
MORE INFORMATION
For additional information on crime scene
investigation, check out Court TV’s Crime Library:
www.crimelibrary.com/criminal_mind/forensics/crimescene/5.html
On Michael Baden and the autopsy:
www.crimelibrary.com/criminal_mind/forensics/autopsy/1.html