Types of Evidence

1. Types of Evidence Photos from Kendall Hunt Publishing Content from various chapters in Forensic Science for High School Students and numerous other sources

2. Lessons for the JonBenet Ramsey Case

3. 1996 homicide investigation of 6 year old JonBenet Ramsey provides valuable lessons in proper crime-scene investigations. • From this case we learn the importance of securing a crime scene.

4. Police in Boulder, Colorado allowed extensive contamination of the crime scene. • Police first thought case was a kidnapping because of a ransom note found by her mother. For this reason they did not search the house until 7 hours after the family called 911.

5. Initially thinking the case was a kidnapping, police did not immediately search the house, and did not find the body of JonBenet in the basement.

6. The police only blocked off JonBenet’s bedroom with crime scene tape to preserve evidence her kidnapper may have left behind. They did not seal of the rest of the house, which later was included as part of the crime scene.

7. The victim’s father discovered the body in the basement. He covered her body with a blanket and carried her to the living room. • Contamination of the crime scene occurred as well as disruption of evidence (which may have identified the killer).

8. Once the body was found, family, friends and police officers remained close by, moving freely around the house. • One friend cleaned the kitchen, wiping down counters with a spray cleaner.

9. Many hours passed before the police blocked off the basement • The pathologist did not examine the body until 19 hours after the crime took place.

10. What is evidence? • 1. Testimony and presentation of documents, records, objects, and other such items relating to the existence or non-existence of alleged or disputed facts into which a court enquires.2. Methods and rules that guide and govern the establishment of a fact before a court, collectively called the law of evidence.

11. Testimonial evidenceis a statement made under oath;also known as direct evidence or prima facie 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. Classification of Evidence

12. 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 Reliability of Eyewitness

13. Eyewitness A police composite may be developed from the witness testimony by a computer program or forensic artist. FACES—a composite program by InterQuest

14. 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 Physical Evidence As a result of the influences on eyewitness memory, physical evidence becomes critical.

15. Physical evidence can be used to answer questions about: What took place at a crime scene The number of people involved The sequence of events Reconstruction A forensic scientist compares the questioned or unknown sample from the crime scene with a sample of known origin.

16. Transient evidence is temporary; easily changed or lost; usually observed by the first officer at the scene. Pattern evidenceisproduced by direct contact between a person and an object or between two objects. Conditional evidenceisproduced 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 is produced by contact between person(s) and object(s), or between person(s) and person(s). Associative evidence is something that may associate a victim or suspect with a scene or with each other; e.g., personal belongings. —Henry C. Lee and Jerry Labriola, Famous Crimes Revisited, 2001 Types of Physical Evidence

17. 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

18. 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 Examples of Pattern Evidence • Blood spatter • Glass fracture • Fire burn pattern • Furniture position • Projectile trajectory • Tire marks or skid marks

19. Light—headlight, lighting conditions, lights on or off 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, odometer mileage Body—position and types of wounds; rigor, livor, and algor mortis Scene—condition of furniture, doors and windows, any disturbance or signs of a struggle Examples of Conditional Evidence

20. Biological—blood, semen, saliva, sweat, tears, hair, bone, tissues, urine, feces, animal material, insects, bacteria, fungi, botanical material Chemical—fibers, glass, soil, gunpowder, metals, minerals, narcotics, drugs, paper, ink, cosmetics, paint, plastic, lubricants, fertilizer Physical—fingerprints, footprints, shoeprints, handwriting, firearms, tire marks, toolmarks, typewriting Miscellaneous—laundry marks, voice analysis, polygraph, photography, stress evaluation, psycholinguistic analysis, vehicle identification Classification of Evidence by Nature

21. Evidence Characteristics Individual—can be identified with a particular person or a single source • Fingerprints - 1 X 1060 • 1 in 1,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000 Fingerprints Blood DNA Typing Class—common to a group of objects or persons

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.

23. Class vs. Individual Evidence, continued Which examples do you think could be individual evidence?

24. Include some or all of these seven major activities: Recognition—the ability to distinguish important evidence from unrelated material Pattern recognition Physical property observation Information analysis Field testing Preservation through the collection and proper packaging of evidence Forensic Investigations

25. Identification using scientific testing Physical properties Chemical properties Morphological (structural) properties Biological properties Immunological properties Comparison of class characteristics 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 Forensic Investigations, continued

26. Individualization in demonstrating that the sample is unique, even among members of the same class Interpretation—giving meaning to all the information Forensic Investigations, continued • Reconstruction of the events in the case • Inductive and deductive logic • Statistical data • Pattern analysis • Results of laboratory analysis —Henry C. Lee and Jerry Labriola, Famous Crimes Revisited, 2001

27. Probability and Class Evidence • A young person was seen leaving a high school parking lot after having been near a car with a broken window; a purse was missing from the passenger seat. The suspect was identified as having light brown hair and wearing a white shirt, blue jeans, and dark colored athletic shoes. • In a school of 1,600 students, how common are these charaterisitics?

28. How many students would be expected to be wearing a white shirt on any given day? Let’s say that in your class of 33 students, seven are wearing a white shirt. What percentage of the class is this? • If this percent is representative of the whole school, how many students in the whole school are likely to be wearing a white shirt? • Is this good evidence?

29. How many students would be wearing blue jeans? In your class you count 12 wearing blue jeans. What percentage is this? • How many students in the school would be wearing blue jeans? • How many students in school are likely to be wearing a white shirt and blue jeans?

30. Now determine how many students would be likely to have light brown hair. In your class you count 5 students with light brown hair. What is the percentage of students with this hair color? • How many students in the school would have light brown hair? • What is the percentage of students that would be wearing a white shirt, blue jeans, and have light brown hair? • How many students in the whole student body would meet that description?

31. Now let’s calculate how 4 pieces of class evidence could affect the probability of nailing the suspect. If four students in your class are wearing dark colored athletic shoes, what is the percentage of your class wearing this type of shoe? • How many students in school would likely be wearing this type of shoe?

32. How many students in school are likely to be wearing a white shirt, blue jeans, have light brown hair, and are wearing dark colored athletic shoes?

33. Can this evidence be Individualized? • A torn t-shirt was found in the backseat of a suspect’s car. A piece of torn cloth was found at the scene of the crime. Can it be individualized to the t-shirt? Explain

34. A pistol was found in a theater where a man was shot. A suspect know to have owned a Derringer like this one was apprehended. Would this gun be considered individual or class evidence?

35. Pieces of a broken bottle were found at the scene of an assault. The bottom of the bottle was found in the suspect’s car. Can the pieces of the bottle be uniquely associated (individualized) with what was found in the suspect’s car? Explain

36. Some blond hairs were found on the gloves of a suspected kidnapper who has brown hair. Would they be considered class or individual evidence?

37. A bloody knife has been found in the backyard of a murder suspect. Under what circumstances could it be individualized? Or will it remain as class evidence?

38. Are tire impression such as these individual or class evidence? Explain

39. Can it be determined whether these bullets and casing were fired from the same gun? How can bullets be individualized to a gun? Explain

40. Some powder was found in a plastic bag in a suspect’s pocket. Some similar powder was found on the victim. Can the first powder be individualized to the second powder? Explain. If the two powders were determined to be chemically identical, does that prove that they came from the same source?

41. A pair of latex gloves was found at the scene of a robbery. A box of the same brand of latex gloves was found at the suspect’s home. Can the gloves be individualized to the box? Explain.

42. Collecting Trace Evidence Who collects the evidence? • Police Officer • Crime Scene Investigator • Forensic Scientist Depends on the state/community Often one person to ensure consistency of labeling

43. Collect trace or entire object? Trace > Collecting • Suppose a glove appears to have glass, fibers and blood on it. • Should the glass, fibers and blood be removed and packaged separately? Should the entire glove be packaged?

44. Considerations before packaging entire object: Trace > Collection • Object may be too large or difficult to move • Trace evidence may fall off item during transport. • Trace Evidence may be transferred to different, irrelevant area of object. If packaging object, package objects separately. Prevents trace being transferred to other objects.

45. These 3 methods can be done at the crime scene or in the crime lab. Trace > Collection 1. Visual Inspection 2. Tape Lift 3. Vacuum

46. Use naked eye or hand lens. Evidence removed and packaged for later analysis Use bright light and forceps to collect. Trace > Collection Visible Inspection

47. Small paper envelopes are bad (Holes allow small objects to escape). Use small plastic bags, glass vial or paper using a druggist fold. Double package. Label each package. Trace > Collection Visible Inspection (Packaging)

48. Clear tape is used. Repeatedly apply tape to small area until most of the stickiness is gone. Tape is folded back upon itself, taped to a glass slide or taped to a piece of plastic. Put in separate labeled container. Be sure to document specific area covered. Trace > Collection Tape Lift

49. Vacuuming Trace > Collection • Nozzle should be short and transparent. • Debris is collected on a filter or membrane

50. Small area is vacuumed. (Filters changed frequently) Filters packaged in separate labeled container. (Be sure to document specific area covered) Most improperly used method because it often results in the collection of a lot of irrelevant material. Trace > Collection Vacuuming