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Welcome to Forensics!

Welcome to Forensics!. What is forensics??. Forensics - application of science to criminal law Science - body of knowledge, organization Criminal law- type of law that sets acceptable limits of conduct in society Misdemeanor : minor criminal violations

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Welcome to Forensics!

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  1. Welcome to Forensics!

  2. What is forensics?? • Forensics- application of science to criminal law • Science- body of knowledge, organization • Criminal law- type of law that sets acceptable limits of conduct in society • Misdemeanor: minor criminal violations • theft, minor assault and battery, small possession of drugs • Felony: major criminal violations • murder, rape, armed robbery, serious assault, dealing drugs, fraud, auto theft, forgery Forensics Crime scene Criminal Court

  3. Forensics Categories

  4. Crime Scene Forensics Criminal Court POLICE ONLY!

  5. Evidence • Evidence- something that proves or disproves a fact • Purpose of Evidence • Prove crime happened • Provide links of suspect/victim to presence at crime scene • Reconstruct a crime scene • Types of evidence • Testimonial- what a person says about the crime • Physical- object that can be touched

  6. Testimonial Evidence Expert Witness- interpret evidence found at the crime scene Eye Witness- person at crime scene Advantages Disadvantages • Advantages • Significant experience in the field • Jury understands significance of evidence • Better understand crime scene • Disadvantages • Still room for interpretation • Expert not at crime scene

  7. Physical Evidence Advantages Disadvantages

  8. 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: ability of evidence to link suspect to crime - The more class evidence, the greater probability linking suspect to the crime (greater probative value)

  9. 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

  10. 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

  11. 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

  12. Processing a Crime Scene 1. Secure & Isolate Crime Scene • Protect lives • Rope off • Protect physical evidence • Separate witnesses • Note conditions • Time, lights on/off, odors, temp

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

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

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

  16. Sketch the Crime Scene • Why make a sketch? • Accurately shows the physical facts and locations of objects at the scene • Permanent record of the scene • Assists in • Interviewing people • Preparing investigative report • Presenting the case in court

  17. Processing a Crime Scene: Cont’d Informal/Rough Sketch Include • Perimeter & evidence measurements (not to scale) • Compass directions • Rough estimation of location of evidence • Date, location, time of incident

  18. How to Make a Rough Sketch • Step 1: Draw perimeter shape of crime scene • Step 2: Label the corners of the perimeter • Step 3: Draw roughly where evidence is located • Step 4: Take measurements of perimeter of crime scene & label on diagram • Step 5: Take measurements to locate evidence at crime scene & label on diagram • Triangulation: 2 reference point measurements • Make sure points of reference are not moveable • Step 6: Put in compass directions, date, time, location at crime scene

  19. Crime Scene Processing: Cont’d Scaled Drawing Include • Perimeter and location of evidence- TO SCALE • Compass directions • Date, location, time of incident • Scale Legend B A D C

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