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Welcome to Forensics!

Welcome to Forensics!. 1. What is forensics??. Forensics- application of science to evidence testing Science- body of knowledge, organization. 2 . Evidence. Purposes of Evidence: Prove crime happened Provide links Reconstruct. Physical- tangible item. Eyewitness- testimonial.

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Welcome to Forensics!

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  1. Welcome to Forensics!

  2. 1. What is forensics?? • Forensics- application of science to evidence testing • Science- body of knowledge, organization

  3. 2. Evidence Purposes of Evidence: Prove crime happened Provide links Reconstruct Physical- tangible item Eyewitness- testimonial Advantages Start investigation Describe the crime Disadvantages Not reliable Accuracy Witness’s safety Credibility • Advantages • More reliable • Scientific testing • Disadvantages • Time availability • Some is not useable • Still need to interpret the evidence • Expert Witness- interpret • evidence found at the • crime scene • Advantages • Jury understands • significance of evidence • Better understand • crime scene • Disadvantages • Still room for • interpretation • Expert not at • crime scene

  4. 3. Individual vs. Class Evidence Individual- belongs to unique, single source Class- belongs to large group of similar objects Hair Fiber Bullet casings Bullet hole Skulls/Bones Broken glass • DNA • Blood • Dental • Fingerprints • Fibers with blood • Handwriting Probative value: must link suspect to the crime! - The more class evidence, the greater probability linking suspect to the crime

  5. 4. Crime Lab Categories Special (expensive & highly specialized) subspecialties

  6. 5. Crime Scene Processing • Locard’s Principle- always _______ of material • Always evidence present • Evidence & technology • Frye decision (1923): Scientific evidence must be given by ______________ _________ and have gained “_________ __________ in that particular field of study • Lie detectors admissible in court? Pgs 8-9 Pg. 15

  7. Crime Scene Processing: Cont’d • Daubert (1993): Debate whether or not evidence was admissible in court • Trial judge must assume responsibility for ___________ and _________ of scientific evidence • P.E.A.T.S • P= peer reviewed • E= error rate • A= acceptance- state by state • T= testable techniques • S= standards (controls) pg. 15

  8. 5. Crime Scene Processing Cont’d • Search & Seizure Considerations • 4th amendment: Protects against ____________ searches & ____________ by state and federal law enforcement ______________ • 1978: Mincey vs. Arizona • No “_______ _______” _______ to the requirement that police obtain a warrant before entering someone’s home • 1978: Michigan vs. Tyler • Seizures of evidence must occur during _______ _________ operation or soon _____ flames are ________. Re-entry later for evidence needs a _________. • Current: May only search and seize evidence in emergency situations only! Otherwise need a warrant

  9. Processing a Crime Scene • Secure & Isolate Crime Scene • Protect lives • Rope off • Protect physical evidence • Note conditions • Time, lights on/off, odors, temp

  10. Processing a Crime Scene: Cont’d • Observe & document the crime scene • Notes • Photo & videotape • Sketch

  11. Processing a Crime Scene: Cont’d • Systematic Search (find the evidence) body body

  12. Processing a Crime Scene: Cont’d • Collect & Process the Evidence • Separate container for each item • Wet, blood  plastic Dry  paper • Controls- samples with known origin • Seal • Initial, time, # • Chain of custody • Who collected • Who had contact • Time • Circumstances

  13. Processing a Crime Scene: Cont’d Crime scene sketches • Informal/Rough Sketch • Measurements included (not to scale) designate N, location of evidence, date location, time of incident • Formal- scaled • Same requirements as rough sketch • Must include measurements

  14. Processing a Crime Scene: Cont’d How to measure 1. Measure important objects in area & space between • HINT: Make sure all measurements of furniture and space between add up to total width or length 2. Evidence location • Coordination- 1 point measurement • Triangulation- 2 point measurement • Make sure points of reference are not moveable • To nearest foot • NO FRACTIONS- JUST DECIMALS!

  15. How to Make a Formal Scale Drawing • Write the dimensions for actual size of room • L=_____ W=______ • Measure size of available drawing space on paper • L=_____ W=_______ • Create scale Actual length of room = Scale value Length of drawing space Scale legend becomes 1” = scale value • Measure and draw dimensions for scaled size of room on paper - Actual length or width ÷ scale value= measurement for drawing • Include the scale legend outside the drawing area • Measure and draw items located within the room • Actual size ÷ scale value= measurement for drawing

  16. Practice Formal Scaled Drawing Calculations N E Scaled dimension of room (steps 1-4) Available drawing space L= 11” W= 8” Scaled drawing measurements (step 6) Doors:_____ Space north of door:_____ Space south of door:______ 8’ E Doors 3’ 18’ 12’

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