CRIME SCENE INVESTIGATION CHAPTER 2 Mr. Moss 1
CRIME SCENE INVESTIGATION Crime scenes tell a story Crime scene investigators must be careful and systematic Crime scene investigators must follow protocol for evidence to be admissible in court 2
CRIME SCENE PROCESSING Timing evidence can be lost with time Plan of Attack systematic search method Attention to Safety safety of scene searchers Appropriate Personnel qualified and trained Controlling Scene authorized personnel only Documentation sketching the scene and establishing a chain of custody for all evidence 3
TYPICAL CRIME SCENE INVESTIGATION 4
Crimes are reported in one of three ways: -by a witness to the crime -by a victim of the crime -by law enforcement while the incident is in progress 5
First Officer on the Scene -Ascertains if perpetrator is on scene hot search (at scene) vs. cold search (left scene) -Tends to injured -Notifies needed personnel (supervisor, medical examiner, CS team) -Secures consent to search -Secures scene & avoid walking through the scene or searching for evidence -Insures safety 6
HOT SEARCH Assumes that perpetrator is still in vicinity of crime scene Thorough search of crime scene and surrounding area Done immediately after crime scene is discovered 7
COLD SEARCH Assumes that perpetrator has fled scene Done hours or days after crime scene has been discovered Covers surrounding neighborhood Residents, etc, canvassed for potential witnesses 8
Initial Scene Examination Follow unit protocol ME or coroner establishes a preliminary PMI to any decedent Body is examined for evidence and transported Survey scene to establish boundaries both inside and out Decide on search method 9
Systematic Search of Crime Scene Videotape & photograph entire scene Decide on search method: grid, line, zone or spiral Evidence is marked & photographed Sketch of crime scene including tented evidence 10
SEARCH METHODS GRID LINE ZONE SPIRAL 11
CRIME SCENE PHOTOGRAPHY Photograph outside with distance and close up views of all access points Room shots show 4 corner views Distance and close up photos of evidence 12
CRIME SCENE RECORDING Videotapes are often taken of scene Automatic 360 degree video may be used Use of digital photography allows incorporation of pictures into reports Photographer has almost immediate access to picture quality, which may determine usability Digital photographs can be enhanced for clarity when present to a jury 13
SKETCH A ROUGH DRAFT A FINAL SKETCH 14
Evidence Collection Results of scientific analysis of evidence is only as good as evidence brought to lab Proper collection, preservation and packaging of evidence is crucial Determination of evidence collectors may depend on seriousness of crime ( simple theft, clandestine drug labs, homicide, etc) Forensic scientists or experts needed at scenes 15
THREE MAJOR STEPS OF EVIDENCE COLLECTION Recognition of Evidence Collection of Evidence Packaging and Preservation of Evidence 16
RECOGNITION OF EVIDENCE Must have ability to recognize evidence team of experts in various types of evidence Look for individual or characteristic qualities of evidence Context of crime, type of crime and crime scene are important to discerning evidence Generally, there is no such thing as too much evidence Collect everything initially, as it is difficult if not impossible to return and collect more evidence- chain of custody and contamination issues 17
EVIDENCE COLLECTION Collect as much evidence as possible Collect trace evidence Collect adequate evidence to allow for testing- defense may want to test separately Probative value or significance of evidence can be enhanced if linked to a known object or material 18
GENERAL ORDER FOR EVIDENCE COLLECTION Tire Impressions Footwear Trace Evidence- Fibers/Hairs Blood/Biological Fluids Latent Fingerprints Entomology Collection of Insect Evidence Toolmarks Firearms Questioned Documents 19
CHAIN OF CUSTODY AUTHENTICATION OF EVIDENCE There are physical, scientific and legal requirements to determine how evidence is packaged Chain of custody a detailed map of the path of the evidence from collection to court Evidence is bar coded for authentication Packaging in tamper-evident packaging 20
PRESERVING EVIDENCE Specific packaging required for different types of evidence Living plants (marijuana): need breathable containers Trace evidence: use evidence or druggist s fold Fire residues: airtight container 21
RECONSTRUCTION OF THE CRIME SCENE Crime scene is a slice of history Each piece of evidence contributes to story Proper collection, packing, and analyzing evidence allows for story to be told in court Evidence links suspect to crime scene Without such evidence or improper collection of evidence, proof beyond a reasonable doubt is difficult to prove in court 22