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Chapter 2: Types of Evidence “You can learn a lot by just watching.” —Yogi Berra, former New York Yankees catcher and sage.

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Presentation on theme: "Chapter 2: Types of Evidence “You can learn a lot by just watching.” —Yogi Berra, former New York Yankees catcher and sage."— Presentation transcript:

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2 Chapter 2: Types of Evidence “You can learn a lot by just watching.” —Yogi Berra, former New York Yankees catcher and sage

3 Chapter 2 Kendall/Hunt Publishing Company 1 Evidence  The difference between indirect and direct evidence  That eyewitness accounts have limitations  What is meant by physical evidence and give examples  What physical evidence can and cannot prove in court  The significance of individual and class evidence Students will learn:

4 Chapter 2 Kendall/Hunt Publishing Company 2 Types of Evidence Two general types:  Testimonial—a statement made under oath; also known as direct evidence or Prima Facie evidence  Physical—any object or material that is relevant in a crime; also known as indirect evidence. Examples are hair, fiber, fingerprints, documents, blood, soil, drugs, tool marks, impressions, glass.

5 Testimonial evidence includes oral or written statements given to police as well as testimony in court by people who witnessed an event. Eyewitness accounts can be a useful tool in helping investigators with analyzing a crime scene, but are not viewed to be highly reliable. In addition, eyewitness identifications (right or wrong) can have a big influence on the outcome of an investigation or trial. People are likely to view the same scene in different ways depending on their positions, line of sight, familiarity with the area, and other factors that can interfere with a person’s ability to remember details. What is testimonial evidence? The Bunny Effect CBS News Video

6 Chapter 2 Kendall/Hunt Publishing Company 4 Reliability of Eyewitness Factors:  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

7 Chapter 2 Kendall/Hunt Publishing Company 5 Eyewitness  A police composite may be developed from the witness testimony by a computer program or forensic artist.  “Perception is reality.”  As a result of the influences in eyewitness memory, physical evidence becomes critical. Faces—a composite program by InterQuest

8 Eyewitness accounts can be a useful tool in helping investigators with analyzing a crime scene, but are not viewed to be highly reliable. People are likely to view the same scene in different ways depending on their positions, line of sight, familiarity with the area, and other factors that can interfere with a person’s ability to remember details. Let’s test your “eyewitness” abilities! You will have 30 seconds to view the next screen. Try to memorize all 20 items you see! Eyewitness Accounts Pros & Cons

9 Chapter 2 Kendall/Hunt Publishing Company 7 Neuroscience for Kids - http://faculty.washington.edu/chudler/puzmatch1.html Items to remember...

10 Chapter 2 Kendall/Hunt Publishing Company 8 What do you remember? You have two minutes to list as many of the items as you can! How did you do? 20 -      15-19 -     10-14 -    5-9 -   4 or less – Wake up!

11 Chapter 2 Kendall/Hunt Publishing Company 9 Facial Composites Investigators work with sketch artists and eyewitnesses to create facial composites, or sketches of a person’s face. Today many police departments are using facial reconstruction software to help them with this task. The composite may be used internally to assist officers in identifying the suspect or used externally through local media (radio, TV, and newspaper) to solicit leads from citizens. FACES Software – Offers many options to help you recreate a person’s facial features.

12 Chapter 2 Kendall/Hunt Publishing Company 10 Value of Physical Evidence  Generally more reliable than testimonial  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

13 Chapter 2 Kendall/Hunt Publishing Company 11 Reconstruction Physical Evidence is used to answer questions about:  what took place  how the victim was killed  number of people involved  sequence of events A forensic scientist will compare the questioned or unknown sample with a sample of known origin.

14 Chapter 2 Kendall/Hunt Publishing Company 12 Types of Physical Evidence  Transient Evidence—temporary; easily changed or lost; usually observed by the first officer at the scene  Pattern Evidence—produced by direct contact between a person and an object or between two objects  Conditional Evidence—produced by a specific event or action; important in crime scene reconstruction and in determining the set of circumstances or sequence within a particular event  Transfer Evidence—produced by contact between person(s) or object(s), or between person(s) and person(s)  Associative Evidence—items that may associate a victim or suspect with a scene or each other; ie, personal belongings —Lee and Labriola in Famous Cases, 2001

15 Chapter 2 Kendall/Hunt Publishing Company 13 Examples of Transient Evidence  Odor—putrefaction, perfume, gasoline, urine, burning, explosives, cigarette or cigar smoke  Temperature—surroundings, car hood, coffee, water in a bathtub, cadaver  Imprints and indentations— footprints, teeth marks in perishable foods, tire marks on certain surfaces  Markings

16 Chapter 2 Kendall/Hunt Publishing Company 14 Examples of Pattern Evidence Pattern Evidence—most are in the form of imprints, indentations, striations, markings, fractures or deposits.  Clothing or article distribution  Gun powder residue  Material damage  Body position  Tool marks  Modus operandi  Blood spatter  Glass fracture  Fire burn pattern  Furniture position  Projectile trajectory  Tire marks or skid marks

17 Chapter 2 Kendall/Hunt Publishing Company 15 Examples of Conditional Evidence  Light—headlight, lighting conditions  Smoke—color, direction of travel, density, odor  Fire—color and direction of the flames, speed of spread, temperature and condition of fire  Location—of injuries or wounds, of bloodstains, of the victim’s vehicle, of weapons or cartridge cases, of broken glass  Vehicles—doors locked or unlocked, windows opened or closed, radio off or on (station), odometer mileage  Body—position, types of wounds; rigor, livor and algor mortis  Scene—condition of furniture, doors and windows, any disturbance or signs of a struggle

18 Chapter 2 Kendall/Hunt Publishing Company 16 Classification of Evidence by Nature  Biological—blood, semen, saliva, sweat, tears, hair, bone, tissues, urine, feces, animal material, insects, bacterial, fungal, botanical  Chemical—fibers, glass, soil, gunpowder, metal, mineral, narcotics, drugs, paper, ink, cosmetics, paint, plastic, lubricants, fertilizer  Physical—fingerprints, footprints, shoe prints, handwriting, firearms, tire marks, tool marks, typewriting  Miscellaneous—laundry marks, voice analysis, polygraph, photography, stress evaluation, psycholinguistic analysis, vehicle identification

19 Chapter 2 Kendall/Hunt Publishing Company 17 Evidence Characteristics  Class—common to a group of objects or persons  Individual—can be identified with a particular person or a single source Blood DNA TypingFingerprints

20 Chapter 2 Kendall/Hunt Publishing Company 18 Class vs Individual Evidence Which examples do you think could be individual evidence?

21 Chapter 2 Kendall/Hunt Publishing Company 19 Forensic Investigations Include some or all of these seven major activities 1. Recognition—ability to distinguish important evidence from unrelated material  Pattern recognition  Physical property observation  Information analysis  Field testing 2. Preservation—collection and proper preservation of evidence

22 Chapter 2 Kendall/Hunt Publishing Company 20 Investigations 3. Identification—use of scientific testing  Physical properties  Chemical properties  Morphological (structural) properties  Biological properties  Immunological properties 4. Comparison—class characteristics are measured against those of known standards or controls; if all measurements are equal, then the two samples may be considered to have come from the same source or origin.

23 Chapter 2 Kendall/Hunt Publishing Company 21 Investigations 5. Individualization—demonstrating that the sample is unique, even among members of the same class 6. Interpretation—gives meaning to all the information 7. Reconstruction—reconstructs the events of the case  Inductive and deductive logic  Statistical data  Pattern analysis  Results of laboratory analysis —Lee, Dr. Henry. Famous Crimes, 2001

24 Chapter 2 Kendall/Hunt Publishing Company 22 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.

25 Chapter 2 Kendall/Hunt Publishing Company 23 People in the News Dr. Henry Lee —Chief Emeritus for Scientific Services and the former Commissioner of Public Safety for the state of Connecticut. He served as that state’s Chief Criminality from 1979 to 2000. Lee was the driving force in establishing the modern forensic lab in Connecticut. He has worked with many high profile cases including O.J. Simpson, Jon Benet Ramsey, and the “wood chipper” case. He is also seen on many of the true crime shows, including his own, “Trace Evidence: The Case Files of Dr. Henry Lee”. Learn more at his website: www.drhenrylee.com/review.shtml

26 Chapter 2 Kendall/Hunt Publishing Company 24 FBI Investigation Read a case investigated by the FBI. Observe the various units of their lab and read the section: “How They Do That?”. www.fbi.gov/kids/6th12th/investigates/investigates.htm


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