1. Processing a Crime Scene
UNIT OVERVIEW
Processing a Crime Scene
Evidence Team
Crime Scene Searches
Evidence Collection and Packaging
Chain of Custody
Legal Precedent
Physical Evidence

2. Locard’s Exchange Principle
Every contact leaves a trace!
Whenever two objects come together they must affect each other in some way. Something is likely to be exchanged between them!
Physical Evidence - encompasses any object that can establish a crime has been committed or can provide a link between a crime and its victim or perpetrator

3. A group of professionals trained in a variety of special disciplines
Crime Scene Team
A group of professionals trained in a variety of special disciplines
First police officer on the scene (Team Leader)
Medics (if necessary)
Photographer and Note taker
Sketch team
Evidence Recovery Personnel
Lab experts/specialists

4. Team Leader (1st Officer)
Secure and Isolate the Crime Scene
Obtain medical attention
Preserve and protect evidence
Exclude unauthorized personnel (Every individual who enters is potential destroyer of evidence)
Designate officer in charge
Establish boundaries
Evaluate area

5. 1) Team Leader Assume control and assess scene
Determine search pattern and assignments
Coordinate with groups involved
Continuously evaluate work
Release Crime Scene

6. Crime Scene Survey Walk-through Purpose:
Mentally prepare a reconstruction theory
Note any conditional evidence that could change over time
Note environmental and weather conditions
Note points of entry or exit, as well as paths of travel within the crime scene
Record initial observations of who, what, where, when, and how
Identify special needs within the crime scene for personnel, precautions, or equipment and notify superior officers or other agencies

7. Recording/ Documenting the Scene
Need to permanently record the crime scene so original state is not lost
Documentation is required for presentation at trial
Photography
Sketches
Notes

8. 2)Note taker
Must include written description of the scene with enough detail to refresh memory months or years later
date, time, description of the location
weather and environmental conditions
description of the crime
location of the evidence relative to other key points
the names of all people involved
modifications that have occurred and other relevant information

9. 3) Photographer Videography
Secondary to still photos
allows for narration (non-subjective) and different perspectives
Photos of entire scene and surroundings (overlap by 30%)
mid-range to close-up photos with various angles of each piece of evidence
Photograph evidence before it’s moved (including fingerprints, casts, etc.)
Photograph evidence both in wide view (position at scene) and close-up (with scale)
All photos logged

10. Capture Crime Scene

11. Wide angle lenses are used to distort the truth or emphasis it

12. Details preserved

13. Proper Technique (Courtesy of Phil Orlando)

14. 38 Caliber and 44 Caliber

15. 4) Sketch Artest (Rough and Finished)
Includes date, time, scale
Gives reference points and distance measurements
Names of investigators, victims, suspects
A legend (key)
Finished Sketch
Can be hand drawn or computer generated
Drawn to scale
Aesthetic appearance

17. 5) Evidence Recovery Personnel
Package evidence separately
Maintain chain of custody and evidence log
Ensure proper safety of collection (e.g., infectious materials)
What to think about?
Who did it?
What happened?
When did it happen?
How did it happen?
Did it happen here or was another crime scene involved?
Who is the victim?
Why was this crime committed?
What evidence is there to help prove the motive and the crime? 

18. Crime Scene Searches Must be thorough and systematic
Search for evidence must be conducted immediately
How investigation is carried out depends on locale, size of area, actions of suspects & victim(s) at scene
Steps:
One person supervises or coordinates collection of evidence
Scene subdivided into segments
Areas searched must include all possible points of entry and exit

19. Methods of Searching a Crime Scene
Line or strip method
Best in large, outdoor scenes
Need many people to be most effective
Move in one direction at a time
Must move slow and
cover the area multiple
times

20. Grid Search A double-line search Effective, but time-consuming
Can be done with fewer people in an large, open area (fields or woods)

21. Zone or quadrant method
Most effective in houses, buildings, or large areas
Teams are assigned zones for searching
Usually based on floor plans or land areas

22. Spiral method Best on small, circular crime scenes
May move inward or outward (being careful not to disturb evidence
Best used where there are no/limited physical barriers

23. Physical Evidence Includes
Anything from massive objects to microscopic traces
Evidence may be obvious, but some can only be detected through examination in the crime lab
Examples:
Victims clothing (Fibers)
Fingernail scrapings
Head and pubic hairs
Blood (for typing and DNA typing purposes)
Recovered bullets
Hand swabs from shooting victims (for gunshot residue analysis)
Soil

24. Collecting & Packaging Evidence
The most fragile evidence is collected and packaged first
Different types of evidence require specific or special collection and packaging techniques
The type of container depends on the sample
Changes can occur through:
Contamination
Breakage
Evaporation
Accidental scratching or bending
Improper or careless packaging

25. Types of Packaging
Many items are packaged in a primary container and then a secondary one.
Pill bottles, vials, manila envelopes, and plastic bags are good for most evidence.
Trace evidence may be placed on a piece of paper which is then folded in a particular way called a “druggist’s fold.”
Secondary containers such as paper bags, plastic bags, canisters, packets, or envelopes are used depending on the type and size of the evidence.

26. Maintaining the integrity of evidence
Item should be kept in original condition if possible
Submit to the lab intact
Blood, hairs, fibers, soil particles - should not be removed from garments, weapons or other items that bear them (send entire object for testing)
Bloodstains and scraping should be transferred to a moistened swab or cut out area of object bearing stain
Biological evidence such as dried blood should be packaged in paper ~ Liquid blood can be collected in a glass tube but SHOULD NOT be frozen
Packages should be sealed and marked with your initials, date collected, and vital information

27. ALL handlers are responsible for the integrity the evidence
Chain of Custody - a written record of all those who have had possession of an item of evidence, beginning at the time of collection (The first person who comes in contact with that evidence should fill out a chain of custody tag.)
The evidence container must be marked for identification.
The collector’s name or initials are placed on the seal.
If evidence is turned over to another person, the transfer must be recorded.

29. Submission to Laboratory
Evidence forms must accompany all evidence
Brief history of case is included
Type of examinations requested
List of items submitted for examination
Obtain Standards/Reference Samples and Controls
Examination of evidence requires a comparison with a control for verification
Quality & quantity of reference samples lends weight to their value

30. Safety Guidelines from the International Association for Identification Safety Committee
Personnel wear a minimum of latex gloves (double gloved) and protective shoe covers.
Use of masks/respirators, goggles or face shields
Be alert to sharp objects (knives, hypodermic needles, razor blades…)
Maintain a red biohazard plastic bag for disposal of potential infectious materials
Note taking done with non-contaminated gloves
Soiled/torn protective equipment should be removed immediately and disinfected
No eating or drinking at the crime scene
Personal clothing that may have been contaminated should never be taken home

31. Legal Considerations at the Crime Scene
“Unreasonable search and seizure” removal of evidence must conform to 4th amendment:
“The right of the people to be secure in their persons, houses, papers and effects against unreasonable searches and seizure, shall not be violated, and no warrants shall issue, but upon probable cause, supported by oath or affirmation, and particularly describing the place to be searched and the persons or things to be seized.”

32. Allowances for Warrantless searches
Existence of an emergency (exigent circumstances)
The need to prevent the immediate destruction of evidence.
In plain view
A search of a person or property within the immediate control of the person provided it is made incident to a lawful arrest.
Consent of the person involved.

33. MINCEY v. ARIZONA (U.S. Supreme Court, 1978)
Legal Precedent
MINCEY v. ARIZONA (U.S. Supreme Court, 1978)
Drug bust that went wrong and an undercover police officer was killed.
Police spent 4 days searching and seizing evidence
Mincey arrested and convicted.
Supreme Court ruled evidence collected was inadmissible because it was not from a proper search and seizure.
Evidence taken without proper authority is probably not legally admissible

34. Michigan v. Tyler (U.S. Supreme Court, 1978)
Building destroyed by fire was put out in early AM.
Building left unsecured until 8 AM when a preliminary search was done (for cause of fire).
Subsequent searches (at 4, 7, and 25 days) removed additional evidence.
Tyler convicted of arson.
However….Supreme Court overturned conviction.
“…entry to fight a fire requires no warrant, and that once in the building, officials may remain there for a reasonable time to investigate the cause of the blaze. Thereafter, additional entries to investigate the cause of the fire must be made pursuant to the warrant procedures”