FORENSIC
SCIENCE
INTRODUCTION
Crime Scene
Investigation
Forensic Science
Definition: The application
pp
of scientific technology
gy to
supply accurate and objective information reflecting
the events that occurred at a crime.
What does a Forensic Scientist DO???
1. .
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2. .
3. .
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Complex Reasoning
In Forensic Science
Deductive
educt ve :
Inductive Reasoning :
Classifying
Comparing and Contrasting
Problem Solving
Analyzing Perspectives
Constructing Support
Error Analysis
The History of Forensic Science
Sherlock Holmes: a fictional character developed by Sir Arthur
Conan Doyle; used a great deal of forensic detection
Mathieu Orfila: toxicology (the detection of poisons)
Alphonse Bertillon: anthropometry (personal identification
through body measurements)
Francis Galton: developed 1st fingerprint identification system
Leone Lattes: determined methods of using blood type as a
means of identification
Calvin Goddard: firearms examination
Albert Osborn: document examination
Edmund Locard: Developed the 1st police lab
J. Edgar Hoover: director of the FBI: Organized the 1st FBI
Crime Lab in 1932
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2
Locard’s Exchange Principle
Whenever 2 objects come in contact with
one another,
L
Locard
d strongly
l believed
b li d that
h
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Branches of Forensic Science
Physical science: Using ________,, ______,,
and __________ to ID and compare crime scene
evidence
Biology:
Pathology, psychology, odontology, any many
more!
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3
CORPUS DELICTI
You must prove:
“Body of the Crime”
È that a crime occurred
È that the person charged with the crime was responsible for the crime
Top Reasons for Committing a Crime
È.
È.
È.
È.
Source of Evidence
È Body
È Primary and/or Secondary Crime Scene
È Suspect(s)
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4 Major FEDERAL Crime Labs:
FBI
Drug Enforcement Administration (DEA)
Bureau of Alcohol, Tobacco, Firearms and
Explosives (ATF)
US Postal Inspection Service
Most states also have their own, smaller crime
labs
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4
General Crime Lab Services
and the materials each unit analyzes
Physical Science Unit: drugs, glass, paint, explosives,
etc
t
Biology Unit: blood and other bodily fluids
Firearms Unit: ballistics, comparisons
Document Examination Unit: handwriting,
typewriting, questioned documents (ransom notes, etc)
Photography
g p y Unit: record all phyhsical
p y
evidence.
Toxicology Unit: presence/absence of drugs
Latent Fingerprint Unit: fingerprints
Pathology Unit9
Forensic Pathology
Investigation
g
of sudden unnatural,, unexplained
p
or
violent deaths
Answer the questions:
Who is the victim?
What are the injuries, when did they occur, and how were
they produced?
5 manners of death:
GO TO SLIDE 37…..
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5
Crime Scene Team
A group of professionals investigators, each trained in a variety of
special disciplines.
disciplines
Team Members
É
É
É
É
É
É
First Police Officer on the scene
Medics (if necessary)
Investigator(s)
Medical Examiner (if necessary)
Photographer and/or Field Evidence Technician
Lab Experts
pathologist
DNA expert
forensic odontologist
forensic psychologist
firearm examiner
document and handwriting experts
serologist
toxicologist
forensic anthropologist
forensic entomologist
bomb and arson expert
fingerprint expert
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INVESTIGATORS
“The
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
to.”
Dr. Henry Lee
Chief Emeritus for Scientific Services and the former Commissioner of Public Safety for
the state of Connecticut
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6
First Officer
at the Scene
ÉA
Assess the crime scene
ÉD
Detain the witness
ÉA
Arrest the perpetrator
ÉP
Protect the crime scene
ÉT
Take notes
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Eye Witness
“Perception
p
is reality.”
y
As a result an eye witness may
not be the best source of
crime scene information.
A police composite may be
developed
p from the witness
testimony by a computer
program or forensic artist.
Faces Composite Program
by InterQuest
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7
Crime Scene
Search Patterns
TWO of FOUR PATTERNS
)Spiral
)Grid
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Crime Scene
Search Patterns
TWO of FOUR PATTERNS
)Strip or Line
)Quadrant or Zone
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8
Crime Scene
Sketch
Date: August 14, 2001
Time: 11:35
Criminalist: Ann Wilson
g Dr
Location: 4358 Rockledge
St. Louis, Mo.
A. Couch/sofa
E
c
B. Female body
D
C. Knife
E. Chairs
E
F. Table
G. Fireplace
G
A
D. Over turned Lampp
F
E
E
E
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Crime Scene Mapping
(outdoors)
ÈAzimuth--uses a compass beam to determine
the location of each piece of evidence
ÈTriangulation--uses two points at the crime
scene to map each piece of evidence
ÈCoordinate or grid--divides the crime scene into
squares
q
for mapping.
pp g
ÈSuspended Polar Coordinate--for use in
mapping evidence in a hole
ÈBaseline--set a north/south line and measures
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each piece of evidence from this line.
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AZIMUTH
Determines:
•Direction
•Distance
•Elevation
TRIANGULATION
Measure from A to B
and then to the
evidence in a
triangular shape.
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Coordinate or
Grid Mapping
Set a north/south
line from a datum
point established
b aG
by
GPS.
S
Make it a perfect square (4 x 4)
by shooting the hypotenuse
and setting in stakes every foot
or meter.
Measure and map
the location of each
ppiece of evidence.
Then collect
evidence and place
in containers by
grid.
Baseline Mapping
Set a north/south line from
the furthest most points
of the crime scene. Then
measure each piece of
evidence from that
baseline. Evidence will
need
eed a numerical
u e ca
measurement where the
piece begins, ends and in
the middle.
Evidence
Baseline
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Suspended Polar
Coordinate
Measure and map each
layer of evidence as
you move down the
hole. Use the
compass readings
from the top to
measure degrees and
a tank dipping line to
measure depth.
MAPPING
TECHNOLOGY
The latest technology
gy
includes this Nikon
Tsunami with computer.
The exact location of all
crime evidence can be
determined and directly
l d d into
loaded
i
a computer
to produce a crime scene
map. Cost = $35,000
for the set.
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Physical Evidence
Transient Evidence--temporary;
É
É
É
É
easily changed or lost; usually
observed by the first officer at the
scene
Odor--putrefaction, perfume,
gasoline, urine, burning, explosives,
cigarette or cigar smoke
Temperature--of room, car hood,
coffee,
ff water
t in
i a bathtub;
b tht b cadaver
d
Imprints and indentations--footprints;
teeth marks in perishable foods; tire
marks on certain surfaces
Markings
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Physical Evidence (cont)
Pattern or Transfer Evidence-produced by direct contact
between a person and an object
or between two objects. There
are several ways (at least 7) of
classifying evidence. In this
class we will use:
class,
ÈBiological
ÈChemical
ÈPhysical
ÈMiscellaneous
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Biological Evidence
ÈBlood
ÈSemen
ÈSaliva
ÈSweat/Tears
ÈHair
ÈB
ÈBone
ÈTissues
ÈUrine
ÈFeces
ÈAnimal Material
ÈInsects
ÈB
ÈBacterial/Fungal
i l/F
l
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Chemical Evidence
ÈFibers
ÈGlass
ÈSoil
ÈGunpowder
ÈMetal
ÈMi
ÈMineral
l
ÈNarcotics
ÈDrugs
ÈPaper
p
ÈInk
ÈCosmetics
ÈPaint
ÈPlastic
ÈL b i
ÈLubricants
ÈFertilizer
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Physical (impression)
ÈFingerprints
g p
ÈFootprints
ÈShoe prints
ÈHandwriting
ÈFirearms
ÈPrinting
g
ÈNumber restoration
ÈTire marks
ÈTool marks
ÈTypewriting
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Miscellaneous
ÈLaundry
y marks
ÈVoice analysis
ÈPolygraph
ÈPhotography
g p y
ÈStress evaluation
ÈPyscholinguistic analysis
ÈVehicle identification
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Physical Evidence (cont)
Conditional Evidence--produced by
a specific event or action; important
in crime scene reconstruction and in
determining the set of circumstances
within a particular event.
ÈLight--headlight; lighting
conditions
ÈSmoke color direction of travel,
ÈSmoke--color,
travel
density, odor
ÈFire--color and direction of the
flames, speed of spread,
temperature and condition of fire
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Conditional Evidence (cont.)
ÈLocation--of injuries
j
or wounds;; of bloodstains;; of the
victims vehicle;of weapons or cartridge cases; of
broken glass, etc.
ÈVehicles--doors locked or unlocked, windows opened
or closed; radio off or on (station); odometer mileage
y p
; types
yp of wounds;; rigor,
g , livor and algor
g
ÈBody--position;
mortis
ÈScene--condition of furniture, doors and windows; any
disturbance or signs of a struggle.
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Cadaver Dogs
Dogs with a sense of smell
100 times better than
humans can sometimes find
what would be overlooked.
They are specially trained
to locate injured, lost
and/or deceased
individuals. They are
trained as air scent dogs or
article (cloth) scent dogs.
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Cadaver Dogs
www.moregionck9search-rescue.com
Dogs are trained to
locate human body
fluids including blood,
hair, teeth, urine, and
semen. The dog on
the left in a training
exercise is trying to
locate clothing with
blood.
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Cadaver Dogs
Looking at a crime scene, humans would probably miss
something as small as this tooth. The dog found it within
minutes of searching the scene.
Evidence
Characteristics
Class--common to a group of objects or persons
Individual--can be identified with a particular person or
source.
ABO Blood Typing
Blood DNA Typing
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Medical Examiner vs
the Coroner
A medical examiner is a medical doctor, usually a
pathologist and is appointed by the governing
body of the area. There are 7 medical
examiners in the state of Missouri and 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.
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Medical Examiner’s
Responsibilities
É.
É.
É Determine a medical _____________-the injury or disease that resulted
in the person dying
É Determine the __________________-the physiological reason that the
person died
É Classify the manner of death
É
É
É
É
É
Natural
Accidental
Suicide
Homicide
Undetermined
É Notify the next of kin
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The Autopsy
Y incision from the left shoulder, down under the nipples and over
to the
h right
i h shoulder.
h ld
Then
Th place
l
the
h scalpel
l l in
i the
h pit
i off the
h
abdomen, below the sternum and cut straight down and left of
the belly button.
Two Methods for Organ Removal--named for two German
pathologists
ÈRokitansky procedure:organs all come out at once.
ÈVirchow procedure: each organ is removed separately and
immediately examined.
A second incision of the body circumnavigates the skull from earto-ear behind the head.
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The Corpse
“The way I see it,
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. Nothingg much new happens,
pp ,
and nothing is expected of you.”
--Mary Roach. Stiff. W. W. Norton & Company. 2003
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THE BODY
Rigor Mortis
Temperature
of body
Stiffness
of body
Time Since
Death
•Warm
•Not stiff
•>
•Warm
•Stiff
•>
•Cold
•Stiff
•>
•Cold
•Not stiff
•>
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THE BODY
Livor Mortis
Livor mortis :
Lividity indicates the ___________________________.
When lividity becomes fixed, then the distribution of
the lividity pattern will not change even if the body’s
position is altered.
p
Lividity usually becomes fixed between 10 and 15 hours
after death.
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THE BODY
Algor Mortis
Algor mortis is _________________. At a crime scene
scene,
it can be obtained in two different ways.
É Rectal temperature
É Liver
Li
temperature
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Time Frame of Death
È
Condition
Appearance
È Periphery
blood drying
30 min to 2 hrs
È Blue-green discoloration of skin
È Right
and left area of abdomen
È Entire abdomen
È Bloating
È Skin
slippage
È Absence of smell from bones
24 hours
36 hours
36 to 48 hours
4 to7 days
more than 1 year
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Time Frame of Death
Eyeball Changes
È Condition
Appearance
È Cornea
drying (eyes open)
minutes
È Cornea drying (eyes closed)
2 hours
È Corneal cloudiness (eyes open) less than 2 hours
È Corneal cloudiness (eyes closed) 12 to 24 hours
È Eyeball collapse
more than 24 hrs
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THEREFORE,
One can die of a massive
massi e hemorrhage (the
mechanism of death) due to a gun shot wound
through the head (cause of death) as a result of being
shot (homicide), shooting yourself (suicide), dropping
a gun and it discharging (accident), or not being able
to tell which (undetermined). All of which are
manners of death.
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CRIME
Why Did It
Happened?
What
Happened?
Crime Scene
Who Did
It?
Investigative Stage
Evidence Collection
Witness, Suspect and
Motive Development
Post Scene
+
Profiling
Means
Motive
=
Identification
and Arrest of
Suspect
Opportunity
Evidence Processing
Cause, manner, time
of death
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Forensic Investigations
Include some or all of these seven major activities
ÉRecognition--ability to distinguish important
evidence from unrelated material
ÉPattern recognition
ÉPhysical property observation
ÉInformation analysis
y
ÉField-testing
ÉPreservation--collection and proper preservation of
evidence
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Investigations (cont)
ÈIdentification--use of scientific testing
ÈPhysical
ÈPh
i l properties
ti
ÈChemical properties
ÈMorphological (structural) properties
ÈBiological properties
ÈImmunological properties
ÈComparison--class
ÈComparison
class characteristics are measured against
those of know standards or controls; If all
measurements are equal, then the two samples are
considered to have come from the same source or
origin.
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Investigations (cont.)
ÈIndividualization--demonstrating that the sample is
unique, even among members of the same class.
ÈInterpretation--gives meaning to all the information
ÈReconstruction--reconstructs the case events
ÈInductive and deductive logic
ÈStatistical data
ÈPattern analysis
ÈResults of laboratory analysis
Lee, Dr. Henry. Famous Crimes. Southington:Strong Books, 2001
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Just A Thought
It’ss not what you know
It
that hurts you, its what
you think you know
and it’s not so
.
. . . .Mark Twain
How does this apply to
forensic science and crime
51
investigations?
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