Crime scene sketching basics

1. Crime Scene Sketching Basics
Tutorial

2. Introduction:
The crime scene sketch:
•Accurately portrays the physical facts
•Relates the sequence of events at the scene
•Establishes the precise location and relationship
of objects and evidence at the scene
•Creates a mental picture of the scene for those
not present
•Is a permanent record of the scene

3. Overview
A crime scene sketch assists in:
1) Interviewing and interrogating persons
2) Preparing an investigative report
3) Presenting the case in court
•The sketch supplements photographs, notes,
plaster casts and other investigative techniques.
Two types of sketches
•Rough sketch
•Finished or scale sketch

4. The Rough Sketch
•The rough sketch is the first pencil-drawn outline
of the scene and the location of objects and
evidence within this outline.
•Usually not drawn to scale
–Although distances are measured and indicated in the
sketch
•Sketch after photographs are taken and before
anything is moved.
•Sketch as much as possible.

5. Sketching Materials
•Paper
•Pencil
•Measuring tape
•Ruler
•Clipboard
•Eraser
•Compass

6. Steps in Sketching the Crime Scene
•Observe and plan
•Measure distances
•Outline the area
•Locate objects and evidence within the outline
•Record details
•Make notes
•Identify the sketch with a legend and a scale

7. Measure and Outline Area
•A steel tape is best
•It doesn’t stretch
•Use conventional units of measurement
–Inches
–Feet
–Centimeters
–Meters

8. Measure and Outline Area
•North should be at the top of the paper.
•Determine Scale
•Take the longest measurement at the scene and divide
it by the longest measurement of the paper used for
sketching.
•½”= 1’small rooms
•¼”= 1’large rooms
•1/8”= 1’very large rooms
•½”= 10’large buildings
•1/8”= 10’large land area

9. Measure and Outline Area
•Measure from fixed locations
–Walls
–Trees
–Telephone poles
–Corners
–Curbs
–Outlets
–Any Immovable Object

10. Plotting Objects & Evidence
•Plotting methods are used to locate objects
and evidence on the sketch.
•They include the use of:
–Rectangular coordinates
–A baseline
–Triangulation
–Compass points.

11. Rectangular Coordinates
•Uses two adjacent walls as fixed points as
distances are measured at right angles

12. Baseline Method
•Run a baseline from one fixed point to
another, from which measurements are taken
at right angles.

13. Triangulation
•Uses straight-line measurements from two
fixed objects to the evidence to create a
triangle with evidence in the angle formed by
two straight lines.

14. Compass Point Method
•Uses a protractor to measure the angle
formed by two lines

15. Cross-Projection Method
•Presents floors and walls as the were on one
surface.

16. Make a Legend
•Contains:
–Case number
–Type of crime
–Investigator
–Persons assisting
–Direction of North
–Identifying information in sketch -Key
–Scale

17. Sample Sketch

18. The Assignment
•Now it’s your turn! In a moment you will visit
a 360
0
Virtual Crime Scene.
•You will need to complete a rough sketch and
finished sketch of all rooms at the crime
scene.
•Be sure to explore all rooms floor to ceiling
and wall to wall.
•Remember to include a legend
•I will provide you with the necessary
measurements to include in your sketches.

19. Sketches Should Include:
•Bodies
•Furniture (tables, chairs, desks, lamps,
couches, etc.)
•Key objects on or near furniture
•Windows, doors
•Weapons or other evidence (bullets, broken
glass, drugs, etc.)
•Blood spatter or prints

20. Important Measurements
•Kitchen 11 X 13
•Living Room 13 X 16
•Study 10 X 12
•Hall 8 X 8
•Conservatory 10 X 11
•Bloody Knife 1’6” from wall
•Kitchen victim – right foot 2’ from wall, left foot 4’ from wall, head
touching wall
•Living room victim – head 1’6” from stairs, left heel 3’ from
cupboard, right knee 4’6” from desk
•Hammer 1’ from chair leg and 3’ from adjacent wall
•Car keys 2’2” from doorway and 3’10” from chair leg
•Shoe 2’5” from conservatory door

21. The Crime Scene
•Visit the virtual crime scene below and begin
sketching!
•http://www.360crimescene.co.uk/virtualtour.phtml

•You will need to scan your completed
sketches, save as a PDF file, and email to me
or upload to Moodle.