Divisions of Crime Lab

1
Divisions of Crime Lab

• Physical Science Unit
• Utilizes chemical tests and modern
  instrumentation to examine
• Drugs
• Paint
• Explosives
• Soil, etc.
• Biology unit
• Blood and DNA
• Hair
• Botanical

2
Divisions of Crime Lab

• Firearms
• Examines firearms, bullets, casings, etc.
• Gun Shot Residue (GSR)
• Document Examination
• Analyze and match
• Handwriting
• Typewriting/printing
• Paper-type
• Ink
• Impressions (ESDA)

3
Divisions of Crime Lab

• Photography Unit
• Record crime scene
• Special photographic techniques
• IR, UV, X-ray
• Others might include
• Toxicology
• Latent fingerprint
• Polygraph
• Voiceprint
• Pathology (ME)

• Anthropology
• Entomology
• Psychiatry
• Odontology
• Engineering

4
The Crime Scene

• Obtain medical attention for anyone injured
• Apprehend suspect(s) if still present
• Preserve and record the scene
• Note everything that took place at the scene
  including whether the door was open or closed
  when you arrived
• Prevent unauthorized people from entering
• Perform a systematic search for evidence

5
Recording the scene

• Photograph the scene
• Before disturbing the scene photograph every inch
  of crime scene
• Use a scale to give perspective in close ups of
  any evidence and note position before moving
• Videotaping may be done instead
• Digital photography is easily altered and so
  cant be used (yet)

6
Recording the scene

• Sketch the scene
• Initially a rough sketch is made showing only
  objects, points of entry, etc.
• Eventually a finished sketch with room dimensions
  and distances to scale must be made
• Drafting software can aid

7
(No Transcript)
8
(No Transcript)
9
Recording the scene

• Take notes
• Describe the scene
• For each piece of evidence located
• Time found
• Location
• Who found
• How it was packaged and label
• To whom it was given next

10
Systematic search for evidence

• Can be conducted by grid, spiral or quadrant
  storing evidence, labeling it carefully and
  marking its location
• Microscopic evidence can be recovered by
  vacuuming with filter device

11
(No Transcript)
12
Storing evidence

• Each piece of evidence must be stored separately
  to avoid contamination
• Materials with bio-evidence cannot be stored in
  airtight containers (destructive)
• Biological fluids samples must be refrigerated
• Arson debris must be stored in airtight containers

13
(No Transcript)
14
Chain of custody

• Each piece of evidence must be accompanied by a
  list of everyone who had possession of item
• Prevent tampering and contamination

15
Processing a body

• Obtain victims clothing for more thorough
  analysis in lab
• Fingernail scrapings
• Hair sample
• Blood sample
• Other bio-samples
• Hand swab (for GSR)