Crime Scene Processing

1. Crime Scene Processing Forensics 4

2. Definition of “Crime Scene” • Any area where potential evidence is found, passed through or interacted with • Primary Crime Scene • Location of original or first criminal act • Secondary Crime Scene • Location of subsequent criminal acts • Example: The site of a homicide vs. the location where the body is left

3. General Processing Procedures • Secure and protect the scene • Record the scene • Search for evidence • Collect and package evidence • Submit evidence for analysis • Reconstruct scene

4. 1: Secure the Scene • Often difficult for the first responder in light of other duties • Observe immediate scene • Identify major physical features and safety concerns • Persons present • Paths into and out of area • Likely boundaries of primary scene • Restrict access

5. 2: Record the Scene • Note taking is the most important aspect of any investigation • Must be legible • Must be detailed • Must be specific • Must never be discarded • Many investigators use pocket tape recorders

6. 2: Record the Scene • Date, time and weather information of crime and investigation • Type of crime • General location and description of crime scene • Names of all investigators, witnesses, police officers, etc. • Measurements of important features of scene and surrounding area • Preliminary sketches, photos and/or video • Have we entered the secured area yet?

7. 3: Search for Evidence • General survey first to pick out notable characteristics • More photos and sketches • Photos should be close-ups, mid-range and wide angle • Use measuring devices where applicable especially on close-ups • Rough sketch at crime scene, scaled sketch later • Search must be systematic and specific • Generally work from outer edges into center • Use extreme caution when entering site

8. 3: Search for Evidence • Search, do not collect evidence • Leave markers for later retrieval of evidence • Tape, flags, markers, etc. • Think 3d, evidence is not always on the ground

9. 3: Search for Evidence • Six major search patterns • Link Method • Point to point – one item leads to another • “Bread crumbs” • Grid Method • Very complete but time/manpower consuming • Line/Strip Method • Often used in very large areas • Again, personnel intensive

10. 3: Search for Evidence • Six major search patterns • Zone Method • Often used in buildings • A single room might be a “zone” • Spiral Method • Search spirals out in circles from center of incident • Wheel/Ray Method • Search fans out in straight lines from center of incident • Limited applications

11. 4: Collect and Package • Use as few people as possible • Limits collection techniques, contamination and mistakes • Collect “most fragile” evidence first • Method of collection varies with type of evidence • This includes the containers evidence is collected in • Sealed completely and identified • Keep a separate log of all evidence • Only once all evidence is collected is the scene “released” to appropriate personnel

12. 5: Submit for Analysis • Often not completed by collecting investigator • May require specific processes or facilities

13. 5: Submit for Analysis • Crime Labs • Can be public or private • Public labs run by national/state/local law enforcement agencies • 4 US Government Labs • FBI • ATF • DEA • USPS • Private labs run by person or corporation • May specialize in one area only (Ex: toxicology) • Retest evidence already examined by public lab

14. 6: Crime Reconstruction • Once analysis is complete, reconstructions often follow • May involve complex live/computer simulations • Investigators try to recreate exactly what happened • Very popular in TV’s “CSI”