Transcript document

Chp. 2
The Crime Scene
Part II
Chp. 2
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Please Do Now
State 4 factors that determine how a
crime scene is searched?
State 4 things that an investigator
might be looking for at a crime scene.
Please list them in your
composition book.
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Chp. 2
Photo:http://www.usatoday.com/news/health/
2002-10-30-evidence-usat_x.htm
CRIME SCENE
SEARCH PATTERNS
 How to conduct a crime
scene search depends on
1.
2.
3.
4.
Location of the scene
Time of day / weather
Type of crime
Details concerning events
of the crime
5. Number of people
available for the search
6. Available equipment
 One person should supervise and coordinate the
Chp. 2 collection of evidence
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TYPES OF CRIME SCENE
SEARCH PATTERNS
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
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VEHICLE SEARCHES
Hit-and-run cases
Outside and undercarriage of car are examined
Look for cross-transfer of evidence between car and
victim (blood, tissue, hair, fibers, fabric impressions,
pain, broken glass,…)
Homicide, burglary, kidnapping
All areas of the vehicle, inside and outside, are
searched
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***Common Types of
Physical Evidence
On a whiteboard list 10 types of physical evidence.
Blood, Semen & Saliva
Fingerprints
Documents
Firearms &
Ammunition
Drugs
Explosives
Fibers
Glass
Hair
Impressions
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Common Types of
Physical Evidence
Organs & Physiological
Fluids
Paint
Petroleum Products
Plastic Bags
Powder Residues
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Serial Numbers
Soil and Minerals
Tool Marks
Vehicle Lights
Wood & Vegetative
Matter
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WHAT EVIDENCE SHOULD
BE COLLECTED?
Body
Blood
Hair
Fibers
Clothing
Fingernail scrapings
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EVIDENCE FROM A BODY
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The search for physical evidence extends beyond
the crime scene to the autopsy room of a deceased
victim.
Medical examiner or coroner carefully examines
the victim to establish a cause and manner of
death.
As a matter of routine, tissues and organs will be
retained for pathological and toxicological
examination.
Arrangements must be made between the
examiner and investigator to secure a variety of
items that may be obtainable from the body for
laboratory examination.
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EVIDENCE FROM A BODY
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The following are collected and sent to the forensic
laboratory:
1. Victim’s clothing
2. Fingernail scrapings
3. Head and pubic hairs
4. Blood (for DNA typing purposes)
5. Vaginal, anal, and oral swabs (sex crimes)
6. Recovered bullets from the body
7. Hand swabs from shooting victims
(for gunshot residue analysis)
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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 12
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done by that department.
What evidence can
you find?
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A styrofoam cup and a Sprite? Bottle (each circled). Also
one shoe and what may be a cub scout cap.
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COLLECTING AND
PACKAGING EVIDENCE
Integrity of evidence must be maintained (prevent
physical evidence from changing on its way to the
crime lab)
Changes could occur through:
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Contamination
Breakage
Evaporation
Accidental scratching
Bending
Loss through improper or
careless packaging
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COLLECTING AND
PACKAGING EVIDENCE
Do NOT remove evidence (such as blood,
hair, fibers, soil particles,etc.) adhering to
clothes, weapons, or other articles
Send the entire object to the lab for
processing
If evidence is sticking to an object in a
precarious way, then it might have to be
removed and packaged
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COLLECTING AND
PACKAGING EVIDENCE
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A detective holds the pliers found in Scott
Peterson’s fishing boat. The hair seen stuck to the
end of the pliers is the sole piece of physical
evidence presented by the prosecution.
http://www.search.com/reference/Scott_Peterson
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COLLECTING AND
PACKAGING EVIDENCE
Blood evidence
found on pants
Note: If bloodstained
material is stored in
airtight containers,
moisture buildup may
encourage mold
growth, which can
destroy evidential
value of blood.
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http://www.wksu.org/news/story/20391
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PACKAGING EVIDENCE
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Each different item or similar items
collected at different locations must be
placed in separate containers. Packaging
evidence separately prevents damage
through contact and prevents crosscontamination.
The well-prepared evidence collector will
arrive at a crime scene with a large
assortment of packaging materials and tools
ready to encounter any type of situation.
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PACKAGING EVIDENCE
Forceps and similar tools may have to be used to pick
up small items.
Unbreakable plastic pill bottles with pressure lids are
excellent containers for hairs, glass, fibers, and various
other kinds of small or trace evidence.
Alternatively, manila envelopes, screw-cap glass vials,
or cardboard pillboxes are adequate containers for most
trace evidence encountered at crime sites.
Ordinary mailing envelopes should not be used as
evidence containers because powders and fine particles
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Chp. 2 will leak out of their corners.
PACKAGING EVIDENCE
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Small amounts of trace evidence can also be
conveniently packaged in a carefully folded paper,
using what is known as a “druggist fold.”
Although pill bottles, vials, pillboxes, or manila
envelopes are good universal containers for most
trace evidence, two frequent finds at crime scenes
warrant special attention.
If bloodstained materials are stored in airtight
containers, the accumulation of moisture may
encourage the growth of mold, which can destroy
the evidential value of blood.
In these instances, wrapping paper, manila
envelopes, or paper bags are recommended
packaging materials.
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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.
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Please Do Now
What is chain of custody?
Why is it important?
Please answer in your
composition book.
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CHAIN OF CUSTODY
Chain of Custody—A list
of all persons who came
into possession of an item
of evidence.
Continuity of possession,
or the chain of custody,
must be established
whenever evidence is
presented in court as an
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CHAIN OF CUSTODY
 Adherence to standard
procedures in recording the
location of evidence, marking it
for identification, and properly
completing evidence
submission forms for laboratory
analysis is critical to chain of
custody.
 EVERY person who handled or
examined the evidence and
where it is at all times must be
accounted for.
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CHAIN OF CUSTODY
There must be a written record of all people
who have had possession of an item of
evidence.

A minimum record would show:
1. Collector’s initials
2. Location of evidence
3. Date of collection
•
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If evidence is turned over to another person, this
transfer MUST be recorded in notes and other
appropriate forms
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CRIME SCENE
RECONSTRUCTION
Stages
 Data collection
 Hypothesis formation
 Examination, testing and analysis
 Determination of the significance of
the evidence
 Theory formulation
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OBTAINING
REFERENCE SAMPLES
Standard/Reference Sample—Physical
evidence whose origin is known, such as
blood or hair from a suspect, that can be
compared to crime-scene evidence.
The examination of evidence, whether it is
soil, blood, glass, hair, fibers, and so on,
often requires comparison with a known
standard/reference sample.
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OBTAINING
REFERENCE SAMPLES
When forensic scientists
examine DNA in the lab, each
sample appears as a unique
sequence of dark bars.
Patterns of bars are compared
to find a match.
In the hypothetical example
shown here, which suspect
left some DNA at the crime
scene? #2
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OBTAINING
REFERENCE SAMPLES
 Autoradiograph from an actual rape
case showing the DNA profiles for one
VNTR locus.
 The lanes marked "M" show a "ladder"
of DNA fragments of known sizes.
 These are loaded onto the gel to provide
an internal ruler--allowing the sizes of
the VNTR alleles to be estimated more
accurately.
 Is there a match?
YES, the DNA profile of
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defendant 1 and forensic sample.
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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
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Submit Evidence to Lab
Evidence submitted to lab in person or by mail
shipment
Usually an evidence submission form
accompanies the evidence (see p. 57)
Specify the type of examination is needed for the
evidence
New evidence may be uncovered during the
examination
Include a list of evidence submitted on the
evidence submission form
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MURDER SCENE
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MURDER SCENE
Ned Doheny, Feb. 16, 1929
What do you see?
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Ned Doheny, son of oil magnate Edward Doheny, lies dead in
the foreground; the body of his friend and assistant Hugh
Plunkett is in the hallway beyond. Los Angeles authorities 33
immediately blamed Plunkett in the murder-suicide
Nicole Simpson / Ron Goldman
murder scene, June 12, 1994
Chp. 2
www.cnn.com
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http://wordpress.com/tag/our-blood/feed/
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
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MURDER SCENE
Most important piece of evidence is the victim’s body
Forensic pathologist
May be aided by:
 Forensic anthropologists
 Forensic entomologists
Forensic pathology: study of medicine as it relates to
the application of the law, especially criminal law
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FORENSIC
PATHOLOGIST
Forensic Pathology involves the investigation
of unnatural, unexplained, or violent deaths.
Forensic pathologists in their role as medical
examiners or coroners are charged with
determining cause of death.
The forensic pathologist may conduct an autopsy
which is the medical dissection and examination of
a body in order to determine the cause of death.
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MEDICAL EXAMINER
AND THE CORONER
 Medical examiner— 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.
 Coroner — 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
 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





Natural
Accidental
Suicide
Homicide
Undetermined
 Notify the next of kin
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FORENSIC
PATHOLOGIST
4 broad determinations to be made:
A.
Cause of Death – medical diagnosis denoting disease or
injury
B.
Mechanism of Death – altered physiology by which
disease/injury produces death (arrhythmia, exsanguination)
C.
Manner of Death
1. Homicide
3. Accidental
5. Undetermined
2. Suicide
4. Natural Causes
D. Time of Death
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NATURE OF DEATH
One can die of a massive 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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CAUSE and MANNER
OF DEATH
Autopsy: medical dissection and
examination of body to determine the cause
of death
Manner of death: video
1. Natural
2. Homicide Click to see the real CSI: Crime Autopsy
3. Suicide
4. Accidental
5. Undetermined
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THE BODY FARM
Click to
See video
Video 2
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THE BODY FARM
3 acres of land owned by the University of Tennessee
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THE BODY FARM
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THE BODY FARM
Day 1
Day 2
Day 4
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Day 3
Day 5
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THE BODY FARM
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ESTIMATING
TIME OF DEATH
Can estimate time of death from
• body temperature (algor mortis)
estimate: [98.4 oF – rectal temp] X 1 hour
1.5°F
• insect action (forensic entomology)
• stomach contents (stage of digestion)
• last known activity (last sighting, newspaper/mail)
• normal postmortem change
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ALGOR MORTIS
The Temperature of Death
Loss of heat by a body (a general rule, beginning
about an hour after death, the body loses heat by 1 to 1
1/2 degrees Fahrenheit per hour until the body reaches
the environmental temperature).
Due to lack of cellular respiration
Temperature in 2 ways: rectal and/or liver temperature
Variables:
Chp. 2
•
•
•
•
Environmental conditions
Person’s state of health at time of death
Naked versus clothed bodies
Lightening, electrocution and asphyxia
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ESTIMATING
TIME OF DEATH
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RIGOR MORTIS
The Stiffness of Death
results in the shortening of muscle tissue and
the stiffening of body parts in the position at
death
occurs within the first 24 hrs. and disappears
within 36 hrs.
Due to build up of lactic acid after respiration
Chp. 2 ceases
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RIGOR MORTIS
Body warm
not stiff
less than 3 hours
Body warm
stiff
3-8 hours
Body cool
stiff
8-36 hours
Body cool
not stiff
more than 36 hours 52
Chp. 2
LIVOR MORTIS
The Color of Death
(postmortem lividity)
results in the settling of
blood in areas of the
body closest to the
ground after heart stops
begins immediately on
death and continues up
to 12 hrs.
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Latin: livor—bluish
color; mortis—of
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death
LIVOR MORTIS
The Color of Death
Lividity indicates the position of the body
after death
When lividity becomes fixed, then the
distribution of the lividity pattern will not
change even if the body’s position is
altered.
Lividity usually becomes fixed between
12- and 15 hours after death
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LIVOR MORTIS
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DESICCATION
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After
Death
Processes
video
Algor mortis
• Change in temperature after death
• Most useful indicator of the time of death during first 24 h
• Roughly 1.5ºC/hour
Livor mortis
• Settling of blood in the body gives off a bluish-purple color
Rigor mortis
• Stiffening of the muscles after death
Autolysis
• Tissue breakdown by the body's own internal chemicals and enzymes
Putrefaction
• The breakdown of tissues by bacteria. These processes release gases that are the chief
source of the characteristic odor of dead bodies.
Mummification
• Dehydration or desiccation of tissues
Skeletonization
• Removal of soft tissue. Occurs largely as a result of insects and animals
Adipocere
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Chp. •2 Formation of a waxy substance due to the hydrogenation of body fat. A moist, anaerobic
environment is required for the formation of adipocere.
POTASSIUM EYE
FLUID MEASUREMENT
After death, red blood cells break open
and potassium enters the (ocular)
vitreous fluid slowly.
 The potassium level rises predictably
after death
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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:
•
•
•
•
•
•
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.
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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
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FORENSIC
ANTHROPOLOGY
concerned primarily with the identification
and examination of human skeletal remains
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FORENSIC
ANTHROPOLOGY
Gender ?
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male
female
male
female
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FORENSIC
ANTHROPOLOGY
Race ?
White
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African American
Native American
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Please Do Now
Explain this sign.
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FORENSIC
ENTOMOLOGY
 Jerry Butler, entomology
professor with the University
of Florida's Institute of Food
and Agricultural Sciences,
examines Hairy Maggot
Blow fly larvae retrieved
from a murder victim.
 Butler, one of only five
forensic entomologists in
Florida and about 100
worldwide, uses larvae to
help police establish the time
and place of death.
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AP photo:Thomas Wright, University of Florida/IFAS
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FORENSIC
ENTOMOLOGY
 study of insects and their relation to a
criminal investigation, commonly used to
estimate the time of death.
Maggots eating a dead cow
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FORENSIC
ENTOMOLOGY
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FORENSIC
ENTOMOLOGY
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ESTIMATING
TIME OF DEATH
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