The Crime Scene
How Evidence Is Gathered
Investigation Team
• Group of Legal and Scientific Professionals
– Detectives
– Police officers
– Prosecutors
– Coroners
– Forensic Specialists
The 7 Ss of Crime Scene
Investigation
Securing the scene
Separating the
witnesses
Scanning the scene
Seeing the scene
Sketching the scene
Searching for evidence
Securing the evidence
Legal Requirements
• 4th Amendment
– No illegal search and seizure: may need
search warrant
• 5th Amendment
– Miranda rights
• Federal Rules of Evidence (FRE 901)
– “Authentication” -- must be what you say it is
– “Chain of custody” -- proper procedures and
handling; identify persons with contact
Finding Evidence
• Need systematic search
• Only one person in control
• Types of patterns to search for evidence
– Spiral
– Grid
– Strip or line
– Quadrant
Spiral Search Pattern
http://www.leelofland.com/wordpress/wp-content/uploads/2008/02/63-spiral-search.JPG
Grid Search Method
http://www.leelofland.com/wordpress/wp-content/uploads/2008/02/65-grid-search.JPG
Strip or Line Search
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Quadrant Search
http://o.quizlet.com/i/tZ1zZmCAScKFB-GRPXtTsw_m.jpg
Collecting Evidence
• Separate different types
• Prevent contamination
– “Phantom of Heilbronn”
• Obtain evidence from victim before
burial
• Follow detailed police procedures
Packaging and Analyzing
Evidence
• Must be placed in appropriate container
• Sealed in evidence bag with collector’s
name along taped edge
• Maintain chain of custody
• Evidence processed in lab by forensic
team
Crime Scene Reconstruction
• Hypothesis of sequence of events
• Make sure evidence matches
hypothesis
• Staged crime scene -- perpetrator
reconstructs scene
Sketching the Crime Scene
• Rough Sketch -- draft representation
drawn at crime scene
– Done to scale
– All objects measured from 2 immoveable
landmarks
• Finished Sketch -- precise drawing
– May be done using CAD program