Crime Scene Investigation Chapter 2

What are three ways that crimes are discovered?

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

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

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

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

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

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

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