1. Chapter 3: Crime Scene Investigation and Laboratory Analysis of Biological Evidence

2.  Requires:  Crime scene examination ▪ Scene security, documentation, collection and preservation of evidence  Laboratory analysis ▪ Utilizes scientific techniques for evidence examination, identification of biological fluids, and the comparison of individual characteristics Forensic Biology by Richard Li2

3.  Protecting and securing the scene:  Duty of the first officer on the scene  Only authorized personnel  Use log sheet  Obtain medical attention if needed  Proper supplies and devices must be utilized ▪ E.g. Disposable suits, face mask, disposable gloves and booties Forensic Biology by Richard Li3

4.  Documentation  Sketch ▪ Rough and Finished  Photographs ▪ Use photo log sheet ▪ Use scale  Video Forensic Biology by Richard Li4

5.  Chain of Custody- lists custody information at every point in time when evidence is handled or transferred Forensic Biology by Richard Li5

6.  Recognition of biological evidence ▪ Corpus delicti evidence ▪ Victim-to-perpetrator linkage evidence ▪ Victim-to-scene linkage evidence ▪ Perpetrator-to-scene linkage evidence ▪ Case-to-case linkage evidence ▪ Modus operandi Forensic Biology by Richard Li6

7.  Locard Exchange Principle:  Cross-transference of evidence occurs when a perpetrator has any physical contact with something or someone else Forensic Biology by Richard Li7 Scene Perpetrator Victim

8.  Searches  Alternate Light Source (ALS)  Types ▪ Spiral ▪ Grid ▪ Strip ▪ Quadrant/Zone Forensic Biology by Richard Li8

9.  Collection  Only done after documentation is complete  Consider collecting entire item if small enough or mobile  Considerations ▪ Bloodstain pattern evidence ▪ Multiple analysis of evidence ▪ Trace evidence ▪ Control samples ▪ Size of the stain ▪ Wet Evidence Forensic Biology by Richard Li9

10.  Packaging and Transportation  Goal: protect and preserve evidence  Avoid heat and humidity  Package items separately  Allow wet items to air dry  Use paper!  Label properly and seal Forensic Biology by Richard Li10

11.  Identification of biological evidence  Comparison of individual characteristics of biological evidence Forensic Biology by Richard Li11

12.  Class Characteristics  Can be placed into a category with other similar materials  Individual Characteristics  Evidence possesses characteristics that share a common origin with a reference sample Forensic Biology by Richard Li12

13.  Final steps:  Reporting results  Expert testimony Forensic Biology by Richard Li13