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CRIME SCENES

CRIME SCENES. BASIC REASONS FOR CRIME SCENE. Reconstruction Focus on key evidence Provide immediate investigative leads Present evidence to the trier of fact. WHAT IS AT A CRIME SCENE. Evidence of events, sequence and time Evidence from the suspect

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CRIME SCENES

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  1. CRIME SCENES

  2. BASIC REASONS FOR CRIME SCENE • Reconstruction • Focus on key evidence • Provide immediate investigative leads • Present evidence to the trier of fact

  3. WHAT IS AT A CRIME SCENE • Evidence of events, sequence and time • Evidence from the suspect • Evidence from the scene on the suspect • Conclusive evidence • Circumstantial evidence • Interpretive evidence

  4. BASIC SCENE STEPS • Arrival issues • Stabilization issues • Scene security • Boundaries • General survey • Overview photos and sketching • Collection and preservation

  5. CRIME SCENE ARRIVAL • Safety of responding personnel • Check the medical condition of the victim • List all responding units • Prevent loss of evidence due to: • Medical aid • Suspect action • Environmental issues

  6. STABILIZE THE CRIME SCENE • Protect the perishable evidence • Exclude all uninvolved personnel • Be aware of what can damage evidence: • GSR • Heat on biological • Alcohol in the body • Isolate the participants • Effects of weather

  7. CRIME SCENE SECURITY • Use tape or guards • Purpose is to restrict access to select few • Log who enters and leaves the scene

  8. SET CRIME SCENE BOUNDARIES • Better to over estimate • Consider entry and exit • Focus on three dimensions

  9. ASSESS THE CRIME SCENE • Who needs to be notified • Supervision • Coroner • Crime lab • Sheriff/city investigators • Specialized assistance • What is critical for immediate processing • Set priorities

  10. JOBS IN PROCESSING SCENE • Photos/video • Fingerprints • Note taking • Bagger/tagger • Collector • Security

  11. GENERAL SURVEY • Limit to one or two persons • Note likely entry/exit points • Note misplaced, foreign objects • Note locations of prints/trace • Prevent contamination • Organize

  12. ORGANIZE • Designate trash areas, command center, smoking areas, equipment areas • Where is the command center, restrooms, food/drink, phones • If night is approaching, how much will be done • Order of processing

  13. SCENE DOCUMENTATION • Photography • Sketches • Note taking

  14. PHOTOGRAPHY • Orientation/overalls • Outside and inside • All directions • All four walls/ all rooms • Doors/ windows • Orientation of evidence with and without labels • Close-up

  15. ORIENTATION • LOCATION ORIENTATION • FRONT/SIDES/BACK OF BUILDING • 360 DEGREES FROM EACH SIDE OF BUILDING • 45 DEGREES FROM CORNER OF BUILDING/AREA

  16. 360 Degree Overall

  17. EVIDENCE LOCATION • AS IS • ORIENTATION/ MIDDLE/ CLOSEUP • MARKERS • ORIENTATION/MIDDLE/CLOSEUP • BEFORE AND AFTER SHOT WHENEVER SOMETHING IS MOVED IN ORDER TO SEE ITEM

  18. NOTE TAKING • Detailed • Chronological • Information such as date/times • Scene description • Items collected, date, and times • Body descriptions • Etc..

  19. CRIME SCENE SKETCHING • Definition: The rough notes and measurements one takes at a scene which shows the key physical measurements of the scene and its evidence location. • Purpose • To document relationship of evidence • To illustrate to others the crime scene • To provide an overall perspective of the scene

  20. CRIME SCENE DIAGRAMS • A diagram is the finished product that is included in the report and/or presented to an audience. • This diagram can be: • Scaled or un-scaled • Hand drawn • Computer generated (CAD) • Animated 3D video clips

  21. Basic Tools for Field Sketching • Tape measures - Preferably Inch/Metric combination • Protractor • Level and string line • Compass with sighting capability • Others such as Optical range finders. Reel measurement, Transits etc.

  22. SKETCH TYPES • Rectangular • Triangulation • XY coordinates • Angular displacement • Grids • Elevations • Cross-projections and 3 D

  23. Rectangular Coordinates • This consists of measuring the X and Y distance from two reference points or walls. • If one is going to plot the data on a computer, this is the preferred method.

  24. Triangulation • A method of measurement traditionally taught to crime scene personnel • Measurements are made directly to each of two permanent reference points • Must have a baseline measurement between the reference points.

  25. Polar or Angular Coordinates • Determine one reference point • Measure items from this reference point by angle and distance • Usually used for outdoor scenes

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