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Do Now: How observant are you?

Do Now: How observant are you? . On a traffic light where is the green located? On Dice, what number is on the opposite side the 6? In which hand is the statute of liberty’s torch? What 2 numbers on a telephone don’t have letters on them? When you walk how do your arms swing? . Bottom.

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Do Now: How observant are you?

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  1. Do Now: How observant are you? On a traffic light where is the green located? On Dice, what number is on the opposite side the 6? In which hand is the statute of liberty’s torch? What 2 numbers on a telephone don’t have letters on them? When you walk how do your arms swing?

  2. Bottom Do Now: How observant are you? 1, both number always?? Right On a traffic light where is the green located? On Dice, what number is on the opposite side the 6? In which hand is the statute of liberty’s torch? What 2 numbers on a telephone don’t have letters on them? When you walk how do your arms swing? 1, 0 Opposite

  3. Chapter 3 Physical Evidence

  4. What is Physical Evidence? • Any and all objects that can establish that a crime has been committed OR • can provide a link between a crime and it’s victim or a crime and its perpetrator.

  5. What is Physical Evidence? • Direct • Circumstantial • Physical • Biological

  6. Evidence "Circumstantial evidence can be, and often is much more powerful than direct evidence". -Robert Precht University of Michigan law professor

  7. Evidence • Much of the evidence against convicted American bomber Timothy McVeigh was circumstantial, for example. • Ryder rental truck, • 5,000 pounds (2,300 kg) of ammonium nitrate fertilizer, nitromethane, and diesel fuel \ • The 2005 murder trial of Scott Peterson trial was another high-profile conviction based heavily on circumstantial evidence. Laci and Conner went missing between Dec. 23 and Dec. 24, 2002 • Phone calls from Amber Frey • Hair

  8. Washington Do Now: How observant are you? Clockwise Penny, nickle Stop and border Which president is on the one dollar bill? Which way does water go down the drain? Which coins have smooth edges? On a stop sign, what is white?

  9. Timothy James McVeigh Day 1 • Objective: • What was used as evidence in the case? • Are their other factors that may have been considered? • Now look at it from the side of the Defense. Day 2 • What would be the role of your expert witnesses? • You will be give 5 minutes to: • Opening argument, expert witness, conclusion

  10. Common Types • Blood, semen, saliva • Documents • Drugs • Explosives • Fibers • Fingerprints • Firearms and ammunition

  11. Common Types 8. Glass 9. Impressions 10. hair 11. Organs and Physiological fluids 12. Paint 13. Petroleum products 14. Plastic bags 15. Plastic, rubber, polymers

  12. Common Types 16. Powder residues 17. Serial numbers 18. Soil and minerals 19. Tool marks 20. Vehicle lights 21. Wood and vegetative matter

  13. Identification vs. comparison And how does it relate to evidence??

  14. Identification • Process of determining a substance’s physical or chemical identity. • Drug analysis • Species determination: human or not • Explosive residue analysis

  15. Identification • Steps Involved: • Design systematic analysis that will always test for that substance • Testing must eliminate all other possibilities • Some substances require 1-10 tests • FS must be prepared to render a conclusion with respect to the origin of the specimen

  16. Comparison • Attempts to ascertain whether two or more objects have a common origin. • Use properties of suspect and control. • Gives conclusions as probability • Two types of characteristics

  17. Comparison:Two types of characteristics • Class characteristics: • Substances can be associated with a group but not individual source • Blood types: use factors in blood • A lot of these can ID suspects at a crime scene • Individual characteristics: • Substances that are related at almost 100% probability • Fingerprints are 1x1060 that 2 peoples are the same

  18. Do Now: What is The Product Rule? (Probability)

  19. The Product Rule (Probability) • Multiplying together the frequencies of independently occurring events • Rolling 2 dices and getting sixes • 1/6 x1/6= 1/36

  20. The Product Rule (Probability)

  21. O.J.’s bloodstain frequencies

  22. Fiber Evidence and the Wayne Williams Trial • Items from residence and station wagon.

  23. Fiber Evidence and the Wayne Williams Trial • Tracking Carpet fiber between the two victims • Assuming: • Carpet installed in one room • 12x5’ room • Total sales divided between 10 states • SO 82 rooms with this carpet in Georgia • Product rule (probability) =1 : 7,792 • Very low chance

  24. Crime scene reconstruction • The method used to support a likely sequence of events by the observations and evaluation of physical evidence, as well as statements made by witnesses and those involved with the incident.

  25. For CSR • Medical examiner • Law Enforcement personnel, • Criminalists

  26. Crime scene reconstruction

  27. Finis’

  28. White Powder Lab

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