crime scene sketching basics

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Post on 05-Dec-2014




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  • 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 doesnt 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.
  • = 1small rooms
  • = 1large rooms
  • 1/8= 1very large rooms
  • = 10large buildings
  • 1/8= 10large 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 its your turn!In a moment you will visit a 360 0Virtual 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 16 from wall
  • Kitchen victim right foot 2 from wall, left foot 4 from wall, head touching wall
  • Living room victim head16 from stairs, left heel 3 from cupboard, right knee46 from desk
  • Hammer1 from chair leg and 3 from adjacent wall
  • Car keys22 from doorway and 310 from chair leg
  • Shoe 25 from conservatory door

21. The Crime Scene

  • Visit the virtual crime scene below and begin sketching!
  • You will need to scan your completed sketches, save as a PDF file, and email to me or upload to Moodle.