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Published byCecily McDowell Modified over 9 years ago
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1 Types of Evidence
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2 Classification of Evidence Testimonial evidence is a statement made under oath; also known as direct evidence or prima facie (pree-mah fay-shee) evidence. Physical evidence is any object or material that is relevant in a crime; also known as indirect evidence. Examples are hair, fiber, fingerprints, documents, blood, soil, drugs, toolmarks, impressions, glass.
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3 Reliability of Eyewitness Factors that affect accuracy: Nature of the offense and the situation in which the crime is observed Characteristics of the witness Manner in which the information is retrieved Additional factors: Witness’s prior relationship with the accused Length of time between the offense and the identification Any prior identification or failure to identify the defendant Any prior identification of a person other than the defendant by the eyewitness
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4 Eyewitness A police composite may be developed from the witness testimony by a computer program or forensic artist. Dove Commercial Sketch Artist Video FACES—a composite program by InterQuest
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5 Physical Evidence Is generally more reliable than testimonial evidence Can prove that a crime has been committed Can corroborate or refute testimony Can link a suspect with a victim or with a crime scene Can establish the identity of persons associated with a crime Can allow reconstruction of events of a crime As a result of the influences on eyewitness memory, physical evidence becomes critical.
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6 Examples of Pattern Evidence Pattern evidence— mostly in the form of imprints, indentations, striations, markings, fractures, or deposits Clothing or article distribution Gunpowder residue Material damage Body position Toolmarks Modus operandi Blood spatter Glass fracture Fire burn pattern Furniture position Projectile trajectory Tire marks or skid marks
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7 Serial killer in California (San Francisco area) in the late 1960s and early 1970s Killed somewhere between 6 – 37 people (no one is sure how many) NEVER CAUGHT MO dressed in all black with various Zodiac symbols on his clothes used a military-style knife and.22 caliber hand gun with a flashlight taped on it targeted white teenage couples, “making out” in cars, or parked at “lover’s lane” females horribly shot/stabbed; several of the male victims survived the attacks Possibly had a Naval/Merchant Marine background. May have been British. Sent letters to the newspapers and police taking credit for murders, giving crime scene information, discussion types of bullets used, etc. and signed them with a Zodiac symbol. It was apparent that the Zodiac wanted his identity to be known eventually but was interested in seeing who would be smart enough to crack his code. THE ZODIAC KILLER
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8 Prime suspect Arthur Leigh Allen authorities investigated him admitted to having had bloody knives in his car on the weekend of the stabbing, but claimed that the blood came from a chicken he had killed for dinner. fingerprints compared to a partial print from one of the cars guns compared to the Zodiac evidence handwriting compared to that of the letters None of the tests came back a match and Allen was let go. In 1991, Michael Mageau (one of the victims) was tracked down and shown a lineup of old photos of Zodiac suspects. He fingered Allen as the killer. Unfortunately, Allen died in 1992 of natural causes before any trial could take place. To date (April 2015), the case remains unsolved. THE ZODIAC KILLER
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9 Evidence Characteristics Individual —can be identified with a particular person or a single source DNA Typing Fingerprints Class —common to a group of objects or persons Hair with root Hair w/o root Blood type Lands and grooves
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10 Class vs. Individual Evidence The large piece of glass fits exactly to the bottle; it is individual evidence. These fibers are class evidence; there is no way to determine if they came from this garment.
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11 Class vs. Individual Evidence, continued Which examples do you think could be individual evidence?
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12 Read Case Study 2.1 Coral Eugene Watts. pp. 37-38 Discuss Read Case Study 2.2 Ronald Cotton. Pp. 38-39 Discuss.
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