1 / 12

Chapter 3

Chapter 3. Physical Evidence. Common Types of Physical Evidence. Blood, semen & saliva Documents Drugs Explosives Fibers Fingerprints Firearms & ammunition Glass. Physical Evidence from A-Z. Hair Impressions Organs and physiological fluids Paint Petroleum products Plastic bags

kalei
Télécharger la présentation

Chapter 3

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Chapter 3 Physical Evidence

  2. Common Types of Physical Evidence • Blood, semen & saliva • Documents • Drugs • Explosives • Fibers • Fingerprints • Firearms & ammunition • Glass

  3. Physical Evidence from A-Z • Hair • Impressions • Organs and physiological fluids • Paint • Petroleum products • Plastic bags • Plastic, rubber, and other polymers • Powder residues • Serial numbers • Soil and minerals • Tool marks • Vehicle lights • Wood and other vegetative matter

  4. Identification vs. Comparison • Identification • the process of determining the physical or chemical identity of a substance • What are some examples?

  5. Examples of Physical Evidence to be identified • Drugs, species determination, explosive residue

  6. Drug Analysis Australian Federal Police via Getty ImagesForensic technicians are often called to identify unknown drugs. A beauty student allegedly tried to smuggle more than 10,000 amphetamine tablets into Australia.

  7. Comparison • Determining whether 2 or more objects have a common origin • What is required? • A standard/reference sample • Results may be reported as probability (frequency of occurrence of an event)

  8. Individual Characteristics • Properties of evidence that can be attributed to a common source with an extremely high degree of certainty • Victor Balthazard probability of 2 identical fingerprints is one in 1X 1060 See Examples on p. 66 Criminalistics

  9. Class Characteristics • Properties of evidence that can only be associated with a group and never with a single source • http://science.howstuffworks.com/forensic-lab-technique.htm/printable • (Video Forensic analysis of a gun) • http://videos.howstuffworks.com/science/fingerprint-videos-playlist.htm#video-3949 • The Black Hand Mob in NYC circa 1903

  10. Examples of Class Characteristics • Paint samples from a hit-and-run • Multiple layered samples increase the probability of “matching” a known sample • http://www.kcra.com/r/24405935/detail.html

  11. Examples of Class Characteristics • Blood • Blood type alone may not be a basis to establish common origin • Product Rule- multiplying together the frequencies of independently occurring genetic markers to obtain an overall frequency of occurrence for a genetic profile (see p. 67)

  12. Who decides? • The weight or significance of physical evidence in a case is usually left to the jury.

More Related