Transcript crime scene-body - knoxhealthscience / FrontPage

CRIME SCENES
BASIC REASONS FOR
CRIME SCENE
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Reconstruction
Focus on key evidence
Provide immediate investigative leads
Present evidence to the trier of fact
WHAT IS AT A CRIME
SCENE
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Evidence of events, sequence and time
Evidence from the suspect
Evidence from the scene on the suspect
Conclusive evidence
Circumstantial evidence
Interpretive evidence
BASIC SCENE STEPS
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Arrival issues
Stabilization issues
Scene security
Boundaries
General survey
Overview photos and sketching
Collection and preservation
CRIME SCENE ARRIVAL
• Safety of responding personnel
• Check the medical condition of the
victim
• List all responding units
• Prevent loss of evidence due to:
– Medical aid
– Suspect action
– Environmental issues
STABILIZE THE CRIME
SCENE
• Protect the perishable evidence
• Exclude all uninvolved personnel
• Be aware of what can damage evidence:
– GSR
– Heat on biological
– Alcohol in the body
• Isolate the participants
• Effects of weather
CRIME SCENE SECURITY
• Use tape or guards
• Purpose is to restrict access to select
few
• Log who enters and leaves the scene
SET CRIME SCENE
BOUNDARIES
• Better to over estimate
• Consider entry and exit
• Focus on three dimensions
ASSESS THE CRIME
SCENE
• Who needs to be notified
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Supervision
Coroner
Crime lab
Sheriff/city investigators
Specialized assistance
• What is critical for immediate processing
• Set priorities
JOBS IN PROCESSING
SCENE
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Photos/video
Fingerprints
Note taking
Bagger/tagger
Collector
Security
GENERAL SURVEY
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Limit to one or two persons
Note likely entry/exit points
Note misplaced, foreign objects
Note locations of prints/trace
Prevent contamination
Organize
ORGANIZE
• Designate trash areas, command center,
smoking areas, equipment areas
• Where is the command center, restrooms,
food/drink, phones
• If night is approaching, how much will be
done
• Order of processing
SCENE DOCUMENTATION
• Photography
• Sketches
• Note taking
PHOTOGRAPHY
• Orientation/overalls
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Outside and inside
All directions
All four walls/ all rooms
Doors/ windows
Orientation of evidence with and without
labels
– Close-up
ORIENTATION
• LOCATION ORIENTATION
• FRONT/SIDES/BACK OF BUILDING
• 360 DEGREES FROM EACH SIDE OF
BUILDING
• 45 DEGREES FROM CORNER OF
BUILDING/AREA
360 Degree Overall
EVIDENCE LOCATION
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AS IS
ORIENTATION/ MIDDLE/ CLOSEUP
MARKERS
ORIENTATION/MIDDLE/CLOSEUP
BEFORE AND AFTER SHOT
WHENEVER SOMETHING IS MOVED
IN ORDER TO SEE ITEM
NOTE TAKING
• Detailed
• Chronological
• Information such as date/times
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Scene description
Items collected, date, and times
Body descriptions
Etc..
CRIME SCENE SKETCHING
• Definition: The rough notes and
measurements one takes at a scene which
shows the key physical measurements of
the scene and its evidence location.
• Purpose
– To document relationship of evidence
– To illustrate to others the crime scene
– To provide an overall perspective of the scene
CRIME SCENE DIAGRAMS
• A diagram is the finished product that is
included in the report and/or presented to
an audience.
• This diagram can be:
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Scaled or un-scaled
Hand drawn
Computer generated (CAD)
Animated 3D video clips
Basic Tools for Field Sketching
• Tape measures - Preferably Inch/Metric
combination
• Protractor
• Level and string line
• Compass with sighting capability
• Others such as Optical range finders. Reel
measurement, Transits etc.
SKETCH TYPES
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Rectangular
Triangulation
XY coordinates
Angular displacement
Grids
Elevations
Cross-projections and 3 D
Rectangular Coordinates
• This consists of measuring the X and Y
distance from two reference points or
walls.
• If one is going to plot the data on a
computer, this is the preferred method.
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Triangulation
• A method of measurement traditionally
taught to crime scene personnel
• Measurements are made directly to each of
two permanent reference points
• Must have a baseline measurement between
the reference points.
Baseline with Distance Only
Pole A
Pole B
191'
57'
59'
60.5'
113'
138'
199'
202'
145'
99'
200'
73'
147'4"
74' 11" 147' 4"
30' 165' 10'
65'
158' 8"
Polar or Angular Coordinates
• Determine one reference point
• Measure items from this reference point by
angle and distance
• Usually used for outdoor scenes
XY Grid Techniques
• Set up a grid of lines of arbitrary size, can
be 6”, 1’, 3’ square.
• Generally use numbers on one axis and
letters on the other. This minimizes error.
• This technique is good for multiple
evidence that would be too detailed to
record by individual points, such as grave
sites, bombings, airplane crashes.
XY Grid Picture
The Grid System for Many Items
N
M
L
K
J
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H
G
F
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D
C
B
A 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19
Transecting Baseline or Straight
Line Coordinates
• Items are measured as above or below a baseline.
• Usually used in outdoor scenes.
• Used where the evidence is along a line and it is
easier to create an arbitrary baseline in order to
simplify the measuring routine.
• Use one tape for the baseline and the other for the
transection distance
63 7/8'
32 7/8'
75 1/16'
33 5/8'
57 3/8'
11 7/8'
A
B
71 1/16'
40 1/16'
26 7/8'
36 5/8'
Sketching Elevation
• Sketching in the outdoor environment can bring
forth unique problems.
• One has to be able to illustrate elevation or
contour change for a varying exterior scene.
• Tools for this technique can be a string line and
level (Brick layer) or a Lock/Abney type level
level.
• Usually one contour diagram is sufficient.
• Making elevation measurements allows for 3D
diagramming.
Elevation Measurments
Level
Line
Measurements of elevation over uneven surfaces
Exploded Views
• This technique has the walls laying flat and
attached to the floor plan.
• It makes it easier to relate measurements
and evidence location to the adjacent floor.
• Problems that this can cause is that it can
take up a lot of room on a sketch pad
SEARCH AND LOCATE
EVIDENCE
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Flag into entry areas
Be systematic
Mark, record, and collect
Packaging and labeling
Order of collection
Preservation
References
WHAT HAPPENED?
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Likely theory
Why?
Alternative theory
Where is pt of entry/exit?
What are sources of contamination?
WHEN DID IT HAPPEN?
• Record items like:
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Light switch positions
Window/door positions
Curtain positions
Mail/newspaper
Dress of victim
WHEN DID IT HAPPEN?
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Insect activity
Rigor mortis
Livor mortis
Body temp
Vitreous
WHY DID IT HAPPEN?
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Motives
Signs of struggle
Sign of burglary
Breaking and entry
WHAT DID SUSPECT LEAVE
BEHIND?
• Near body
• Point of entry/exit
WHAT DID SUSPECT
REMOVE?
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Property
Trace
Physiological fluids
Exemplar collection
WHAT TYPES OF DEFENSE
ARGUMENTS TO EXPECT?
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Accident
Suicide
Homicide
The other guy did it