1. A look into evidence gathering and processing
The Crime Scene
A look into evidence gathering and processing

2. Crime Scene Definition
Crime Scene vs. Scene of the Crime
Includes planning areas, flight paths, staging areas, surveillance
Location of the actual crime

3. What is the Job Title?
In the United States, crime scene investigators are usually called “criminalists”
In the United Kingdom, crime scene investigators are usually called
“scene of crime officers”

4. What is the Job Title?
Job titles in forensic fields vary widely from jurisdiction to jurisdiction
Example: A crime scene analyst is a civilian employed by the police department in Las Vegas
- allowed to carry guns
- depending on the department, analysts can be civilian or law enforcement

5. What is the Job Title?
In Albany, 8 detectives make up a “support unit” that collects all areas of evidence instead of individual units

6. Evidence Types
1. Physical or Real evidence: A tangible object related to a crime.
2. Testimonial evidence: Verbal accounting of an incident by a witness, victim or suspect.

7. Evidence Types cont.
3. Direct evidence: That which, if true, proves a fact in dispute.
4. Indirect or circumstantial: That which if true tends to establish an issue in dispute by proving another associated fact which supports the original evidence.

8. Value of Evidence
Physical evidence: Can’t lie, die, quit forget ….etc.
Testimonial evidence: may change, be unreliable, mistaken or source can become unavailable during the case.

9. Physical Evidence Issues
Not recognized, identified or overlooked
Not legally collected
Not properly collected
Not properly packaged
Not properly stored
Not properly tested
Chain of custody issues

10. Evidence Issues continued
Most of the mistakes made in the collection, securing and testing of evidence can be attributed to the lack of training and understanding.
Ex. OJ Simpson Case
- mishandled evidence

11. Class versus Individualized Evidence
Class evidence - evidence that can only be grouped into a general category; cannot be pinpointed to a direct person or object
ex. Black Lab Hair
Individualized evidence - evidence that can be pinpointed to only one individual or object; unique
ex. Fido’s hair (a black Labrador) through DNA

12. Class versus Individualized continued
Trace Evidence
Hair
Class
Dog Hair
Black Labrador Retriever Hair
DNA from hair individualized to Fido (a black Labrador Retriever)
Individualized

13. “Common Source” Not “Match”
When two objects share a class identity
For example, white tennis shoes
Common source can be the factory, owner, or even where found
Suspect who owns white tennis shoes and one is left at crime scene, try to see if the CS shoe came from a common source as the one in his apartment
Example, fibers on a body in ditch
Fibers on body belong to an automobile
Find a suspect, and try to see if fibers in his car are from common source as the fibers on the body

14. Processing the Crime Scene
Crime labs need evidence to function
- Anything which is legally submitted to a court as a means of ascertaining the truth of an alleged matter of fact under investigation before it.
- includes evidence that provides a link between the victim and the assailant
Specifically, they need physical evidence

15. Processing the Crime Scene
Important to remember that crime labs DO NOT solve crime
Only investigations by police solve crimes
Forensics merely helps the police to do their job

16. Priorities of a Crime Scene
Save and preserve life
Provide first aide
Arrest, detain, remove any suspect
Make sure scene is safe for entry by investigators and forensic examiners
Secure and preserve crime scene, keeping record of all who enter/exit

17. Priorities of a Crime Scene
Record and preserve evidence that is perishable
Identify and locate any witnesses; keep separate if possible
(Don’t want stories to be contaminated)
8. Communicate with senior officer who will coordinate initial investigation

18. Secure and Isolate the Crime Scene
The first officer on the scene must follow the previously listed priorities
First priority is to administer first aide and arrest the perpetrator
Must also take efforts to remove unauthorized persons from the scene
Crime scene is marked off, often larger than is and an enter/exit area created

19. Secure and Isolate the Crime Scene
All who enter must be logged in/out; controls evidence tampering
Protective clothing is put on to avoid cross-contamination
The enter/exit area of the perpetrator is recorded as well
Police must ensure suspect can not return to the scene to destroy evidence

20. Record the Scene Limited time available to work a crime scene
Three methods of crime-scene recording:
Photography
Sketches
Notes

21. Lockard’s Theory: Review
Dr. Edmund Locard’s theory for the exchange of evidence is widely recognized as the cornerstone of forensic science.
Locard’s theory: Whenever two objects come into contact, a transfer of material will occur. Evidence that is transferred can be used to associate objects, individuals or locations.

22. Forensic Photographers
Important: Scene must be unaltered
- if changed, photos could be inadmissible as evidence
Photos are taken of entire crime scene, including surrounding areas; enter and exit areas taken at various angles; adjacent rooms
Bodies are also heavily photographed in relation to where they are in the scene

23. Forensic Photographers
As physical evidence surfaces, they are photographed; often with something next to them to indicate size (ruler or measuring tape)
Photographers are only able to begin taking photos once they have been given the okay from the crime scene manager

24. Forensic Photographer
Equipment:
35mm and digital (not evidence) cameras; corresponding film
Standard light (flash)
Colored filters, light beams, UV (stains/fingerprints after treated with superglue or DFO), violet (gunshot residue/blood), blue and green light (prints/fibers/urine/semen)

25. Forensic Photographer
Key point about photography is that it allows the police to reopen a crime scene quickly, like a busy street
- all evidence has been captured on film
Ready 24/7
Extremely difficult job because reliant on this person’s experience to get all data

26. Sketches
After the photographer is finished, crime scene investigators make a rough sketch of scene
Shows the location of all objects
Objects are located from two fixed points in the room like walls or a doorknob; called DATUM
All measurements are made with a tape measure

27. Sketches Often use number or letter cards by evidence
Finished sketch is finished back at the lab using computers and drafting materials

28. Notes Notes are continuously gathered at a crime scene
Must identify the time evidence was found, location, description, who and how item was packaged
Notes can also be taken using a tape recorder and by video; later must all be written down

29. Systematic Search for Evidence
A thorough, systematic search of the crime scene necessary for court
Not necessarily done by forensic scientists
There are four general search patterns
1) Spiral search
2) Grid method
3) Strip or line method
4) Quadrant or zone search

30. Systematic Search for Evidence
Spiral
Grid
Line/Strip
Quadrant/
Zone

31. Systematic Search for Evidence
A hand-held vacuum with a special filter can be used to collect evidence
Crime scene evidence is extended into the autopsy room:
victim’s clothing; fingernail scrapings; head and pubic hairs; blood; vaginal, anal and oral swabs; recovered bullets from the body; hand swabs from shooting victims

32. Collect and Package Physical Evidence
Each different item or similar items collected at different locations must be placed in separate containers
Pill bottles, manila envelopes, and paper bags are common evidence containers; sealed with tape
Forceps are used to pick up small items
Evidence is then sent to lab for examination
Note: Bloody objects DO NOT go in plastic bags; mold grows!

33. Evidence Collection Kit

34. Sample Packaging Information needed on evidence collected
Date and time of collection
Case identification number
Who collected it
Description of item or items collected
Where found
Chain of custody - document that shows record of the evidence’s movement from the time of collection until it is presented in court

35. Maintaining a Chain of Custody
As evidence is collected, the evidence bag is initialed by the collector and dated
Anyone who possess the evidence during the investigation must sign for it as a record
Failure to document can have evidence excluded from case/trial