1. CRIME SCENES

2. BASIC REASONS FOR CRIME SCENE
Reconstruction
Focus on key evidence
Provide immediate investigative leads
Present evidence to the trier of fact

3. 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

4. BASIC SCENE STEPS Arrival issues Stabilization issues Scene security
Boundaries
General survey
Overview photos and sketching
Collection and preservation

5. 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

6. 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

7. CRIME SCENE SECURITY Use tape or guards
Purpose is to restrict access to select few
Log who enters and leaves the scene

8. SET CRIME SCENE BOUNDARIES
Better to over estimate
Consider entry and exit
Focus on three dimensions

9. 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

10. JOBS IN PROCESSING SCENE
Photos/video
Fingerprints
Note taking
Bagger/tagger
Collector
Security

11. 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

12. 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

13. SCENE DOCUMENTATION
Photography
Sketches
Note taking

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

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

16. 360 Degree Overall

25. EVIDENCE LOCATION AS IS ORIENTATION/ MIDDLE/ CLOSEUP MARKERS
BEFORE AND AFTER SHOT WHENEVER SOMETHING IS MOVED IN ORDER TO SEE ITEM

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

41. 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

42. 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

43. 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.

44. SKETCH TYPES Rectangular Triangulation XY coordinates
Angular displacement
Grids
Elevations
Cross-projections and 3 D

45. 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.

47. 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.

49. Polar or Angular Coordinates
Determine one reference point
Measure items from this reference point by angle and distance
Usually used for outdoor scenes

51. 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.

52. XY Grid Picture

53. 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

55. 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.

57. 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

59. SEARCH AND LOCATE EVIDENCE
Flag into entry areas
Be systematic
Mark, record, and collect
Packaging and labeling
Order of collection
Preservation
References

60. WHAT HAPPENED? Likely theory Why? Alternative theory
Where is pt of entry/exit?
What are sources of contamination?

61. WHEN DID IT HAPPEN? Record items like: Light switch positions
Window/door positions
Curtain positions
Mail/newspaper
Dress of victim

62. WHEN DID IT HAPPEN? Insect activity Rigor mortis Livor mortis
Body temp
Vitreous

63. WHY DID IT HAPPEN? Motives Signs of struggle Sign of burglary
Breaking and entry

64. WHAT DID SUSPECT LEAVE BEHIND?
Near body
Point of entry/exit

65. WHAT DID SUSPECT REMOVE?
Property
Trace
Physiological fluids
Exemplar collection

66. WHAT TYPES OF DEFENSE ARGUMENTS TO EXPECT?
Accident
Suicide
Homicide
The other guy did it