NOVEMBER 7, 2012 WARM-UP: STANDARD-SFS1b. Distinguish and categorize physical and trace evidence.

1. NOVEMBER 7, 2012 WARM-UP: STANDARD-SFS1b. Distinguish and categorize physical and trace evidence. EQ: How is physical evidence analyzed? Sit quietly, and I will put up an observation picture in just a minute.

2. PHYSICAL EVIDENCE

3. What evidence can be found at a crime scene? Brainstorm with your group to come up with a list of evidence you might find at a crime scene. Blood, semen, and saliva Documents Drugs Explosives Fibers Fingerprints Firearms and ammunition Glass Hair Impressions Organs and physiological fluids Paint Petroleum products Plastic bags Plastic, rubber, and other polymers Powder residues Soil and minerals Tool marks Vehicle lights Wood and other vegetative matter

4. Biological Evidence Impression Evidence Manufactured Evidence Evidence that comes from living material Evidence that makes markings , prints, tracks, and impressions Evidence that is man-made

5. Categorize the evidence as the following: BIOLOGICAL IMPRESSION MANUFACTURED

6. IDENTIFICATION The process of determining a substance’s physical or chemical identity.

7. COMPARISON The process of determining whether two or more objects have a common origin.

8. INDIVIDUAL CHARACTERISTICS Properties of evidence that can be attributed to a common source with an extremely high degree of certainty

9. Individual Characteristics • Examples: • the matching ridge characteristics of two fingerprints • the comparison of random striation markings on bullets or tool marks • the comparison of irregular and random wear patterns in tire or footwear impressions • the comparison of handwriting characteristics • the fitting together of the irregular edges of broken objects in the manner of a jigsaw puzzle • matching sequentially made plastic bags by striation marks running across the bags PHYSICAL EVIDENCE

10. CLASS CHARACTERISTICS Properties of evidence that can be associated only with a group and never with a single source

11. CRIME SCENE RECONSTRUCTION

12. Figure 3–9  Crime-scene reconstruction relies on the combined efforts of medical examiners, criminalists, and law enforcement personnel to recover physical evidence and to sort out the events surrounding the occurrence of a crime.

13. Figure 3–8  A laser beam is used to determine the search area for the position of a shooter who has fired a bullet through a window and wounded a victim. The bullet path is determined by lining up the victim’s bullet wound with the bullet hole present in the glass pane.