1. Crime Scene Investigation
Chapter 2

2. What are three ways that crimes are discovered?

3. First Officer at the Crime Scene
Determine if perpetrator is still at the scene
Perform hot search (cold search is when you interview neighbors)
Tend to the injured
Secure the scene
Minimize contamination, limit number of people at scene
Do not walk through the scene and search for evidence
Formulate a search plan
Note any obvious safety hazards
Strange smells (chemicals), weakened structures, fire or electrical hazards

4. Crime Scene Investigation
If dead body
forensic pathologist certifies person is dead and determines postmortem interval (PMI)- time since death
Body is processed and removed from scene
Preliminary Investigation
Safety hazards addressed
Fix the boundaries of the crime scene- determine if multiple crime scenes

5. Systematic Search of Crime Scene
Photograph the scene
Determine search pattern
Recording the Crime Scene
Hand drawn sketches
Photographs
Scale drawings- on computers

6. Collection of Evidence
Recognition of evidence
Homicide-
weapon, blood, fibers, hair, fingerprints
Burglaries
tools, glass, soil, fingerprints
Rape
hair, fibers, body fluids
Once evidence is located, exact location must be recorded
Photographed, measurements with respect to fixed object
Necessary for crime scene reconstruction
Once a scene is released to owners, it is not possible to come back and collect more evidence

7. 2. Collection of evidence
As much evidence as possible should be collected
Defense must be given an opportunity to test evidence also

8. 3. Packaging/preservation All evidence must be authenticated
Must be a record of who was in possession of evidence from crime scene till it is used in court (chain of custody)
Evidence must be in tamper evident packaging
Bag must be cut or torn to open, custody form signed and dated for who has custody of evidence

9. Evidence must be preserved
Living plants
breathable containers
Wet blood or body fluids
allowed to dry or breathable container
Wet paint
allowed to dry and placed in breathable container
Trace evidence such as hairs, fibers, small paint chips, glass, powder
placed in envelope or plastic bag within a piece of paper with a druggist fold
Fire residue
air tight container so accelerant doesn’t evaporate