Transcript File

FORENSIC
SCIENCE
The Crime Scene Team
Bell Work for Wednesday,
September 2
* Who makes up the CSI team?
* What are the protocols when approaching a
crime scene?
2
Complex Reasoning
In Forensic Science
Members of the CSI Team
must employ the
following skills:
 Deductive reasoning
 Communication
 Logic
 Observation
 Patience
 Methodical Approach
How are your deductive reasoning
skills?
When Mrs. Jackson came back
from lunch, there were
several messages on her
desk. By changing each digit
of the phone numbers to one
of the three corresponding
letters on the telephone
buttons, can you determine
her relationship to each
caller?
(Answers are on the next slide)
4
5
Deductive Reasoning Answers
â 336-8478
â (222)686-2868
â 774-6837
â 487-2263
â 247-5463
â 832-2437
dentist
accountant
printer
husband
airline
teacher
6
CORPUS DELICTI
Corpus delicti (body of the crime) is a legal term
that refers to the principle that proof of a crime
must occur before a person can be convicted of
the crime.
Therefore the CSI team must prove:
â that a crime occurred
â that the person charged with the crime was responsible for
the crime
Sources of Evidence needed for proof:
â Body/Victim(s)
â Primary and/or Secondary Crime Scene
â Suspect(s)
7
Crime Scene Team
The CSI Team is a group of
professional investigators, each
trained in a variety of special
disciplines.
Team Members
ã First Police Officer on the
scene
ã Medics (if necessary)
ã Lead Investigator
ã Medical Examiner (if
necessary)
ã Photographer
ã Field Evidence Technician
ã Note Taker
ã Sketch Artist
8
Crime Scene Team (cont)
Although they do not actually work at the crime scene,
the laboratory technicians analyze the evidence and
provide answers to the investigators.
The Lab Team includes:
pathologist
DNA expert
forensic odontologist
forensic psychologist
firearm examiner
Document/handwriting experts
serologist
toxicologist
forensic anthropologist
forensic entomologist
bomb and arson expert
fingerprint expert
9
The Role of Each Team Member
Each member of the team has a very specific job
that occurs in a specific time frame. For
example, the evidence technician cannot collect
the evidence until the photographer has finished
taking pictures and the sketch artist has
completed a rough draft. This is an established
protocol that must be followed at every crime
scene.
10
The Protocol
A crime or suspected death has occurred, a telephone call
has been placed to 911 and the police are dispatched
to the scene.
Listen to real 911 calls:
http://www.911callers.com/
The First Officer at the Scene is the lead crime scene
member. The acronym ADAPT explains his/her role.
11
First Officer
at the Scene
ãA
Assess the crime scene
ãD
Detain any witnesses
ãA
Arrest the perpetrator
ãP
Protect the crime scene
ãT
Take notes
12
ADAPT
1. The First Officer on the Scene will assess the scene
to determine if the scene is safe, if there is a victim
that needs assistance and identify all escape routes.
Medics will be called if needed.
2. Next, the officer will instruct potential witnesses to
remain at the scene.
3. Arrests will be made if warranted.
4. The officer will secure the scene with crime scene
tape.
5. After the scene is secure, the officer will monitor the
entrance and begin security log notes.
13
The Lead Investigator
The lead investigator will be the first member to
work the scene. He/she has a limited amount of
time to observe the scene in an untouched state.
The lead investigator determines the boundaries
of the crime scene, identifies any
entrances/exits and completes an initial walkthrough to gain an overview of the situation and
a plan for examining and documenting the
scene.
14
Primary vs. Secondary Crime
Scenes
The Lead Investigator may soon realize that there are
other locations related to the crime scene under
investigation. These locations would be secondary
scenes.
A primary crime scene is the location where the offense
occurred. Secondary scenes are any locations that are
related and may provide evidence.
For example, in a bank robbery, the bank is the primary
crime scene. The getaway car and apartment where the
robbery plans were finalized are secondary scenes.
15
An Investigator’s Job According to
Dr. Lee
“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
16
Crime Scene
Search Patterns
The Lead Investigator will determine will type of
search pattern to implement. There are four main patterns.
Spiral
Grid
17
Crime Scene
Search Patterns (cont)
Strip or Line
Quadrant or Zone
18
An Outdoor Crime Scene
Many times a crime scene
is located outside. While
the roles of the crime
scene team remain the
same, the search patterns
are markedly different.
An outdoor crime scene is
mapped. The mapping
style depends on the
scene.
19
Photographer
Once the lead investigator
has completed an
overview of the scene,
the photographer will
enter the scene.
The photographer will
begin taking wide view
photographs of the
scene.
20
Photographer (cont)
After the Evidence
Technicians have
identified and numbered
the evidence, the
photographer will take
close photographs of
each piece of evidence.
These photographs must
include a ruler to provide
a reference to size.
21
Evidence Technicians
The technicians will begin a through, methodical
search for evidence using the search pattern
determined by the lead investigator.
Physical evidence may be anything from large
objects to microscopic traces. Therefore, it is
important to collect objects that may carry trace
evidence.
All evidence must be collected, packaged and
labeled according to established protocol.
22
Chain of Custody
The evidence technicians
must maintain the chain
of custody.
This is a chronological
documentation of each
piece of evidence.
If the chain of custody is
not maintained then the
court case is
compromised.
23
Contamination
In addition to maintaining
the chain of custody,
each team member has to
take precautions to not
contaminate the
evidence.
Wearing gloves is the most
important precaution.
24
Warm Up
* What does ADAPT mean?
* Define the Chain of Custody
* What are the four search patterns?
* Continue to work on your crime scene
* Each student should have a rough draft sketch, table
completed.
* On poster board, pictures and your final sketch
should be on here as a group effort.
25
The Sketch Artist
Once photographs have been taken, the sketch
artist must complete a rough sketch.
The rough sketch must include:
A compass heading that indicates North
A Legend for all objects in the sketch
Correct Measurements
Points of entry/exit
Date, time and location
26
Crime Scene Sketch Example
(Rough)
27
The Final Sketch
The sketch artist will use the rough sketch as a
guide when creating the final sketch.
All items on the rough sketch must be included on
the final sketch.
The final sketch should be drawn to scale using
graph paper or a computer.
28
Crime Scene Sketch Example
(Final)
Date: August 14, 2001
Time: 11:35 a.m.
Criminologist: Ann Wilson
Location: 4358 Rockledge Dr
St. Louis, Mo.
A. Couch/sofa
E
c
B. Female body
D
C. Knife
E
F. Table
G. Fireplace
G
A
D. Over turned Lamp
E. Chairs
B
F
E
E
E
29
The Sketch Artist (cont)
If any eye witnesses can give a
description of the suspect(s),
the sketch artist will create a
composite sketch. This
composite may be hand
drawn or computer
generated.
Of course, the sketch is only as
good as the information from
the eye witness.
How reliable is an eye witness?
30
Reliability of Eyewitness
Factors:
 The nature of the offense and the situation in which the
crime is observed.
 The characteristics of the witness.
 The manner in which the information is retrieved.
Additional factors:
 The witness’s prior relationship with the accused.
 The length of time between the offense and the
identification.
31
A TRUE EYEWITNESS
Crazy Criminal
As a female shopper exited a New York
convenience store, a man grabbed her purse
and ran. The clerk called 911 immediately and
the woman was able to give them a detailed
description of the snatcher. Within minutes,
the police had apprehended him. They put him
in the car and drove back to the store. The
thief was then taken out of the car and told to
stand there for a positive ID. With that he
replied, “Yes, Officer. . That’s her. That’s the
lady I stole the purse from.”
32
The Sketch Artist (cont)
When skeletal remains are found and the identity
is unknown, the artist may recreate an image
through facial reconstruction.
This is a 3-Dimensional Technique where clay is
applied directly to the skull following contours
and tissue depth markers.
Often the artist has to make an educated guess in
regards to the hair and eyes.
33
Case Solved Due to Facial
Reconstruction
The Skull
The Model
Case Solved
34
The Note Taker
Notes must be taken throughout the processing of the
crime scene.
The notes must include:
A detailed description of the scene and evidence.
The time, method and technician that discovered and
collected any piece of evidence.
The names, reasons and times for anyone that enters the
crime scene.
Notes may be handwritten, tape-recorded or videorecorded.
35
The Medical Examiner
The Medical Examiner will be
called when there is a corpse.
Any evidence on the corpse and
the corpse itself is property
of the M.E.’s office.
The M.E. will take photographs
and temperatures at the
scene.
The corpse will be bagged and
the rest of the investigation
will occur at the M.E.’s
office.
36
A Lost Corpse
Occasionally the evidence
indicates that there
should be a corpse yet
none is located at the
scene.
A different approach is
needed in this
circumstance.
37
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.
38
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. Her name is
Cinder.
39
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.
After the Scene has been Processed
The evidence is delivered
to the team members at
the crime lab.
These forensic scientists
will examine and
analyze each piece of
evidence.
Their findings/results will
dictate how the
investigates continues.
41
Investigative FlowChart
Why Did It
Happened?
What
Happened?
Crime Scene
Evidence Collection
Witness, Suspect and
Motive Development
Post Scene
+
Investigative Stage
Profiling
Means
Motive
Opportunity
Who Did
It?
=
Identification
and Arrest of
Suspect
Evidence Processing
Cause, manner, time
of death
42
Just A Thought
It’s not what you know
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
43
investigations?