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Forensic Science Identification and Individualization.

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Presentation on theme: "Forensic Science Identification and Individualization."— Presentation transcript:

1 Forensic Science Identification and Individualization

2 Types of Evidence  Testimonial  Physical  Testimonial  Physical

3 Testimonial Evidence  Eyewitness testimony usually given in the form of statements made under oath  Dependant upon witnesses’ ability to remember facts as they were  Eyewitness testimony usually given in the form of statements made under oath  Dependant upon witnesses’ ability to remember facts as they were

4 Factors that Affect Eyewitness Testimony  Humans filter out what our minds evaluate to be “unimportant information”.  Humans interpret what we see, looking for patterns and making connections.  Human memory is affected by the emotional state we are in at any given moment.  Humans filter out what our minds evaluate to be “unimportant information”.  Humans interpret what we see, looking for patterns and making connections.  Human memory is affected by the emotional state we are in at any given moment.

5 Second chance at being a good eyewitness!!

6 Physical Evidence  Any object or material that is relevant to a crime.  Generally involves the use of scientific principles to make interpretations:  Chemistry  Biology  Physics  Materials Science  Statistics  Any object or material that is relevant to a crime.  Generally involves the use of scientific principles to make interpretations:  Chemistry  Biology  Physics  Materials Science  Statistics

7 Every contact leaves a trace. Every contact leaves a trace. Locard’s Principle

8 Evidence Testimonial Physical

9 Evidence Direct Indirect / Circumstantial

10 Give an example of each…  Direct Testimonial  Circumstantial Testimonial  Circumstantial Physical  Direct Physical  Direct Testimonial  Circumstantial Testimonial  Circumstantial Physical  Direct Physical

11 Evidence Class Individualized

12 Analysis of Physical Evidence  Class Evidence  The evidence can be classified or placed into a group with other items having the same general properties  Individualized Evidence  Item is unique and be shown to be directly associated with a specific individual source  Class Evidence  The evidence can be classified or placed into a group with other items having the same general properties  Individualized Evidence  Item is unique and be shown to be directly associated with a specific individual source Class evidence is valuable because it can exclude many sources/suspects, but only individualized evidence can point directly to a single source/suspect.

13 Is all evidence admissible in a court??? Rules of Evidence

14 The Frye Standard  The Frye v. United States decision set guidelines for determining the admissibility of scientific evidence into the courtroom.  To meet the Frye standard, the evidence in question must be “generally accepted” by the scientific community.  The Frye v. United States decision set guidelines for determining the admissibility of scientific evidence into the courtroom.  To meet the Frye standard, the evidence in question must be “generally accepted” by the scientific community.

15 Frye gets amended… However, in the 1993 case of Daubert v. Dow the U.S. Supreme Court found that the Frye standard was not absolute. Instead, trial judges were given the responsible of determining the admissibility of scientific evidence presented in their courts. However, in the 1993 case of Daubert v. Dow the U.S. Supreme Court found that the Frye standard was not absolute. Instead, trial judges were given the responsible of determining the admissibility of scientific evidence presented in their courts.

16 The Daubert Criteria How a judge gauges “new science”: 1) Has the science been tested? 2) Has the science has been subject to peer review? 3) Has the science been accepted within the scientific community? 4) What is the rate of error? How a judge gauges “new science”: 1) Has the science been tested? 2) Has the science has been subject to peer review? 3) Has the science been accepted within the scientific community? 4) What is the rate of error?

17 Explore!! pages 6 & 7 in workbook

18 In this class, you will convince “the judge” (Mrs. D) by creating photo comparisons:  in focus!  zoomed in enough to clearly see the features that you are describing  clearly labeled  accompanied with a written description below the photo  in focus!  zoomed in enough to clearly see the features that you are describing  clearly labeled  accompanied with a written description below the photo To be convincing, photo comparisons must be:

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24 Explore!! pages 6 & 7 in workbook


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