CRIME SCENES

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CRIME SCENES
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BASIC REASONS FOR CRIME SCENE

• Reconstruction
• Focus on key evidence
• Provide immediate investigative leads
• Present evidence to the trier of fact

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WHAT IS AT A CRIME SCENE

• Evidence of events, sequence and time
• Evidence from the suspect
• Evidence from the scene on the suspect
• Conclusive evidence
• Circumstantial evidence
• Interpretive evidence

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BASIC SCENE STEPS

• Arrival issues
• Stabilization issues
• Scene security
• Boundaries
• General survey
• Overview photos and sketching
• Collection and preservation

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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

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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

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CRIME SCENE SECURITY

• Use tape or guards
• Purpose is to restrict access to select
  few
• Log who enters and leaves the scene

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SET CRIME SCENE BOUNDARIES

• Better to over estimate
• Consider entry and exit
• Focus on three dimensions

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ASSESS THE CRIME SCENE

• Who needs to be notified
• Supervision
• Coroner
• Crime lab
• Sheriff/city investigators
• Specialized assistance
• What is critical for immediate processing
• Set priorities

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JOBS IN PROCESSING SCENE

• Photos/video
• Fingerprints
• Note taking
• Bagger/tagger
• Collector
• Security

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GENERAL SURVEY

• Limit to one or two persons
• Note likely entry/exit points
• Note misplaced, foreign objects
• Note locations of prints/trace
• Prevent contamination
• Organize

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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

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SCENE DOCUMENTATION

• Photography
• Sketches
• Note taking

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PHOTOGRAPHY

• Orientation/overalls
• Outside and inside
• All directions
• All four walls/ all rooms
• Doors/ windows
• Orientation of evidence with and without labels
• Close-up

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ORIENTATION

• LOCATION ORIENTATION
• FRONT/SIDES/BACK OF BUILDING
• 360 DEGREES FROM EACH SIDE OF BUILDING
• 45 DEGREES FROM CORNER OF BUILDING/AREA

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360 Degree Overall
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EVIDENCE LOCATION

• AS IS
• ORIENTATION/ MIDDLE/ CLOSEUP
• MARKERS
• ORIENTATION/MIDDLE/CLOSEUP
• BEFORE AND AFTER SHOT WHENEVER SOMETHING IS MOVED
  IN ORDER TO SEE ITEM

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NOTE TAKING

• Detailed
• Chronological
• Information such as date/times
• Scene description
• Items collected, date, and times
• Body descriptions
• Etc..

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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

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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
• Scaled or un-scaled
• Hand drawn
• Computer generated (CAD)
• Animated 3D video clips

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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.

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SKETCH TYPES

• Rectangular
• Triangulation
• XY coordinates
• Angular displacement
• Grids
• Elevations
• Cross-projections and 3 D

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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.

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Polar or Angular Coordinates

• Determine one reference point
• Measure items from this reference point by angle
  and distance
• Usually used for outdoor scenes

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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.

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XY Grid Picture
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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

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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.

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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

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SEARCH AND LOCATE EVIDENCE

• Flag into entry areas
• Be systematic
• Mark, record, and collect
• Packaging and labeling
• Order of collection
• Preservation
• References

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WHAT HAPPENED?

• Likely theory
• Why?
• Alternative theory
• Where is pt of entry/exit?
• What are sources of contamination?

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WHEN DID IT HAPPEN?

• Record items like
• Light switch positions
• Window/door positions
• Curtain positions
• Mail/newspaper
• Dress of victim

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WHEN DID IT HAPPEN?

• Insect activity
• Rigor mortis
• Livor mortis
• Body temp
• Vitreous

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WHY DID IT HAPPEN?

• Motives
• Signs of struggle
• Sign of burglary
• Breaking and entry

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WHAT DID SUSPECT LEAVE BEHIND?

• Near body
• Point of entry/exit

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WHAT DID SUSPECT REMOVE?

• Property
• Trace
• Physiological fluids
• Exemplar collection

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WHAT TYPES OF DEFENSE ARGUMENTS TO EXPECT?

• Accident
• Suicide
• Homicide
• The other guy did it