1. Basic Crime Scene Sketching
Chapter 2
Thanks to Special Agent Thompson for helping
Mrs. Warren put this together

2. Sketches
Hand-made pictorial representation of conditions at a crime scene
Helps to clarify investigative data
Explains the relative position, appearance, and condition of physical things which may be material to the investigation
Purpose of sketch is for reconstruction of crime scene

3. When do we sketch? Death scenes Serious personal injury Sex crimes
Serious property damage
Whenever necessary to convey the facts
FBI always sketches

4. Sketches Supplement Photos
Photographs
Provide great detail
Do not always show true and accurate relationships
Cannot determine distances
Sketches
Eliminate unnecessary detail
Show true and accurate relationships
Determine distances

5. Secure the Scene Exclude everyone without an official function
Approach scene carefully and systematically  Have a plan!
Preserve the relationships of objects
Do not alter the position of any object until photographed and recorded
Position, location, or relationship to other items is often as important as the object itself
Record through notes, photographs, and sketches

6. Materials Required Clipboard Pencil and ERASER Ruler Tape measures
Compass

7. Reference Points Must be accurately described on sketch
Must be relatively permanent (likely to still be there 10 years later
Fixed points
Door frames
Room corners
Outside
Utility poles
Manhole covers
Building corners
Can be created (iron stake)

8. Three sketch methods Baseline Used 90% of the time
Establish a baseline (points A and B) and describe all evidence in relation to these points
Typically use the back of the room, but can use other places (like the middle of the room)
Show outline of the room, doorways, and all evidence
Leave out things that are not relevant
All measurements go on table, no measurements on sketch

9. Baseline example Item Baseline Distance from baseline A B N S E W
A = NW corner
B = NE corner
A → B = 24 ft.
Item
Baseline
Distance from baseline
1 = Casing #1
3 ft.
12 ft. 4”
2 = Gun
5 ft. 8”
7’ 2”
3 = Casing #2
6’ 4”
4 = Body
17’ 4”
10’ 6”

10. Three sketch methods Triangulation
Quickest method when only have a few items
Need two reference points
Measure distance to item from each reference point
Again, put data in a table, not on sketch itself

11. Triangulation ExampleS E W
A = Base of door frame,
west
B = Base of door frame,
east A B
Item A B #1
12’ 2”
10’ 6”

12. Three sketch methods Rose Compass Used by FBI ERT members
Best for outdoors
Orient with a magnet compass so that 0° is aligned with north
Only reference point is the center
Triangulate to center
Can use iron stake
Item
Degrees
Distance 1
45 °
32’ 6” 2
330 °
28’ 7” 3
85 °
42’ 1”

13. Important Considerations
Write down all measurements
Fill in all details on rough sketch while at the scene
Do not sketch on the same paper as the notes
Measurements must be accurate (within reason)
Critical distances should be checked by two officers

14. Required Information On ALL sketches include in a title block:
“NOT TO SCALE”
Magnetic north
Case number
Date
Location (address)
Name of sketcher and any assistants

15. Clean Sketch Clean sketch is done with a ruler back in the office
Typically still not drawn to scale
Usually don’t use graph paper
Retain rough sketch as notes