Crime Scene Investigation & Documentation

1. Crime Scene Investigation & Documentation

2. Purpose of a scene search • To obtain physical evidence pertinent to solving a crime

3. Physical Evidence • Physical Evidence must be recognized, accurately documented, properly collected and transported, and a chain of evidence must be maintained before it can be of forensic value. • Manpower and fiscal restraints must be considered relative to the nature of the crime.

4. Preservation of the Crime Scene • First officer on the crime scene must: • Obtain medical assistance • Arrest the perpetrator • Secure the scene (to prevent destruction of evidence) -- May require limiting access to a single room in a motel or sealing off an entire block after an urban fire

5. Observation is key

6. Count Finished files are the results of years of scientific study combined with the experience of many years

7. Once secure, always approached the scene: • in a serious manner (never casually) • in an open, unbiased manner (never have preconceived ideas). • Murders have been bungled because the investigator thought it was a natural death or a suicide

8. Steps in Scene Investigation • Hands in pocket walk-through to observe scene and plan approach. • Minimum number of investigators. • Establish a path of entry and exit (path least likely used by the criminal). • Never take convenience and expedience over thoroughness.

9. Homicide Scene • Efforts of Law Enforcement and Medical Investigator must complement at the scene. • Medical Examiner is there just to see body in perspective – their hands on examination happens back in the autopsy lab

10. Documentation of Scene • Notes • Photographs • Diagrams

11. Scene Notes • Accurate • Brief • Legible • Tape record, then transcribe later—carefully!

12. Photography • Color photo’s • Mirrors in tight places • Photograph objects before moving • Photograph the scene thoroughly • Use scales in photos • Videos (beware of the sound) • Fisheye Lenses and Virtual Images

13. Hand Drawn Diagrams • Entirety of the scene can be illustrated • Insert labels and distance measurements • Document the location and relationship of evidence obscured by vegetation, soil, ashes, or other materials

14. Two Types of Drawings • Rough Sketch • Finished Drawing

15. Rough Sketch • Made by the investigator on the scene • Not necessarily drawn to scale (includes proportions and distances) • No changes to sketch after leaving scene • Soft pencil, graph paper, straight edge, compass, clipboard

16. Elements of Sketching • Scale diagram appropriately • Compass Direction with north arrow • lnclude essential items only • Document the scale (words or figure) • Legend with symbols to identify objects • Title with case identification, location, date, and the sketcher

17. Documenting the Location of Evidence • Rectangular Coordinates • Polar Coordinates

18. Rectangular Coordinates • Triangulate from perpendicular boundaries Bed 2’ from N wall 18” from W wall Dead guy

19. Polar Coordinates • Degrees from north and distance 185 degrees 120’ 135 degrees 390’

20. Global Positioning System (GPS) • for remote areas

21. Projection Sketch • a three-dimensional sketch to allow better illustration of evidence on walls

22. D Bed 2’ from N wall E 18” from W wall C B A Dead guy A-E – bullet holes

23. Finished Drawing • Primarily for courtroom presentation

24. Remember: • When a crime scene is investigated, it is destroyed. The only place it will ever exist after the investigation is in the investigator’s notes, photographs, and diagrams.