3 2 Types of Physical Evidence Unit 3

  • Slides: 10
Download presentation
3 -2 Types of Physical Evidence Unit 3: Physical Evidence October 26, 2014 Sanders

3 -2 Types of Physical Evidence Unit 3: Physical Evidence October 26, 2014 Sanders 8: 33 PM

Types of Evidence • Circumstantial evidence is evidence that relies on an inference to

Types of Evidence • Circumstantial evidence is evidence that relies on an inference to connect it to a conclusion of fact – Scott Peterson had no physical evidence that linked him to the crime • Direct evidence supports the truth of an accusation directly – No need for any additional evidence or inference. 24 December 2021 Physical Evidence 8: 33 PM

"Locard's Exchange Principle" • Every time someone enters an environment, something is added to

"Locard's Exchange Principle" • Every time someone enters an environment, something is added to and removed from it. The principle is sometimes stated as “every contact leaves a trace”, and applies to contact between individuals as well as between individuals and a physical environment. 24 December 2021 Physical Evidence 8: 33 PM

Biological Evidence • Biological crime scene evidence includes – – – – Blood Semen

Biological Evidence • Biological crime scene evidence includes – – – – Blood Semen Saliva DNA Hair Organs Physiologic fluids 24 December 2021 Physical Evidence 8: 33 PM

Impression Evidence • Impression crime-scene evidence is material that includes – – – Tire

Impression Evidence • Impression crime-scene evidence is material that includes – – – Tire markings Glove/fabric marks Tool marks Bite marks Footprints 24 December 2021 Physical Evidence 8: 33 PM

Manufactured Items • Many common crime -scene evidence includes – – – Firearms Ammunition

Manufactured Items • Many common crime -scene evidence includes – – – Firearms Ammunition Fibers Paint Glass Petroleum products 24 December 2021 – – Physical Evidence Plastic bags Rubber Polymers 8: 33 PM

Blood, Semen, Saliva • Materials may be found at crime scene. – Dried –

Blood, Semen, Saliva • Materials may be found at crime scene. – Dried – Liquid Cigarette butts, common source of saliva residue. 24 December 2021 • Subjected to serological biochemical analysis Physical Evidence 8: 33 PM

Documents • Any handwriting or typewritten document can be evaluated for authenticity. – Paper

Documents • Any handwriting or typewritten document can be evaluated for authenticity. – Paper – Ink – Burned or charred items. 24 December 2021 Physical Evidence 8: 33 PM

Drugs • Any substance seized that is in violation of laws regarding controlled substances.

Drugs • Any substance seized that is in violation of laws regarding controlled substances. – – 24 December 2021 Sale Manufacture Distribution Use of drugs Physical Evidence 8: 33 PM

Firearms • The testing of firearms is called ballistics. • Ballistics compares spent ammunition.

Firearms • The testing of firearms is called ballistics. • Ballistics compares spent ammunition. • Size of residue left on gun shot indicates distance of fire. 24 December 2021 Physical Evidence 8: 33 PM