CHE113PhysEvid

CHE113PhysEvid - Physical Evidence Chapter 3 CHE 113 CHE...

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Unformatted text preview: Physical Evidence Chapter 3 CHE 113 CHE 113 1 Physical Evidence ♦ ♦ ♦ ♦ ♦ ♦ ♦ ♦ ♦ ♦ Blood, Semen, Saliva Documents Drugs Explosives Fibers Fingerprints Firearms and Ammunition Glass Hair Impressions CHE 113 CHE 113 2 Physical Evidence ♦ ♦ ♦ ♦ ♦ Organs and Physiological Fluids Paint Serial Numbers Tool Marks Other CHE 113 CHE 113 3 Physical Evidence ♦ Identification - Determination of physical or chemical identity of a substance with as near absolute certainty as the analytical method will permit. – What is the material? How certain is the answer? What analytical method(s) will give the best answer (multiple methods)? ♦ Comparison - Compares standard and suspect samples to determine if they have a common origin. – Can the source of the sample be identified? How certain is the correlation? How many “data points” are necessary to be “certain beyond a reasonable doubt” of the answer (probability)? CHE 113 CHE 113 4 Identification - Determination of the physical and chemical identity of a substance with as near absolute certainty as existing analytical techniques will permit. analytical ♦ Examples: drug analysis, Examples: species determination & explosive residue that contain dynamite. contain ♦ Example: Gas Example: Chromatography / Mass Spectrometry (GC/MS). Accurate identification of a compound. compound. CHE 113 CHE 113 5 Comparisons ♦ Analysis of a suspect specimen WRT Analysis a standard/reference (exemplar) specimen to determine whether or not they have a common origin. common Common Origin? CHE 113 CHE 113 6 Physical Evidence ♦ Class (Group) Characteristics - Properties of evidence that can only be associated with a general group and not with a common source. e.g., blood type, paint or dye lot, etc. e.g., ♦ Individual Characteristics - Properties of evidence that can connect a sample and standard to a common source (with high probability). e.g., fingerprints, unusual wear patterns, tool marks, etc. marks, CHE 113 CHE 113 7 Physical Evidence ♦ Class (Group) Characteristics - Properties of evidence that can only be associated with a general group and not with a common source. e.g., blood type, paint or dye lot, etc. Blood Types World: Type A - 42% Type B - 8% Type O - 47% Type AB - 3% “Bodies of Evidence” Brian Innes CHE 113 US: Type A - 39% Type B - 13% Type O - 43% C Type AB HE5%8 - 113 Class Characteristics Where is Waldo? • Properties of evidence that can only be associated with a group and never with a single source. • Can be used to exculpate a suspect. • Examples: single-layer paint chip, blood, nylon fiber from a sweater CHE 113 CHE 113 9 Class Characteristics Where is Waldo? • Properties of evidence that can only be associated with a group and never with a single source. • Can be used to exculpate a suspect. • Examples: single-layer paint chip, blood, nylon fiber from a sweater CHE 113 CHE 113 10 Physical Evidence ♦ Class (Group) Characteristics - Properties of evidence that can only be associated with a general group and not with a common source. e.g., blood type, paint or dye lot, etc. e.g., ♦ Individual Characteristics - Properties of evidence that can connect a sample and standard to a common source (with high probability). e.g., fingerprints, unusual wear patterns, tool marks, etc. marks, Example: from “My Cousin Vinny” (20th Century Fox) CHE 113 CHE 113 11 Physical Evidence ♦ One-to-many ♦ One-to one CHE 113 CHE 113 12 Physical Evidence ♦ Class or Individual?? CHE 113 CHE 113 13 Physical Evidence ♦ Class (Group) Characteristics - Properties of evidence that can only be associated with a general group and not with a common source. e.g., blood type, paint or dye lot, etc. dye ♦ Example: from “My Cousin Vinny” (20th Century Fox) Example: “My – 2 people charged with murder during a robbery at a people convenience store (“Sack-O-Suds”). convenience – Escaped in an older car and skidded tires while leaving. – Witnesses confused but say they saw the two defendants. – Expert from FBI called to match tire skids with Expert defendants car. defendants CHE 113 CHE 113 14 Class Physical Evidence CHE 113 CHE 113 15 Advantages of Class Physical Evidence Use of Class Evidence Effect of “Scientific Expert” on Jury Effect “Scientific Right to have “counter experts” Right “counter Provides corroboration of events based on objective Provides scientific data scientific The chances of encountering 2 indistinguishable items of The class evidence that originated from different sources are variable. are Multiple types of class evidence may lead to an extremely Multiple high chance that they originated from the same source. high Physical evidence has great weight in the courtroom. Class evidence may also serve to exonerate a person. CHE 113 CHE 113 16 Advantages of Class Physical Evidence Multiple types of class evidence may lead to an extremely Multiple high chance that they originated from the same source. high Type AB blood - 3% Rh Negative - 16% Left-handed - 13% Male - 50% Blood Types World: Type A - 42% Type B - 8% Type O - 47% Type AB - 3% Probability for random match = 0.03 x 0.16 x 0.13 x 0.50 = 0.00031 or ca. 3 in 10,000 US: Type A - 39% Type B - 13% Type O - 43% CHE 5% Type AB - 113 17 CHE 113 Advantages of Class Physical Evidence Multiple types of class evidence may lead to an extremely Multiple high chance that they originated from the same source. high Type AB blood = 3% Rh Negative = 16% Left-handed = 13% Left-handed Male = 50% And Red Haired = 3% And Over 6’2” = 5% Probability for random match = 0.03 x 0.16 x 0.13 x 0.50 x 0.03 x 0.05 = 0.00000047 or ca. 5 in 10 million CHE 113 CHE 113 18 Disdvantages of Class Physical Evidence Next Film Clip Shows Many Impt. Ideas about evidence: Disadvantages of Class Evidence (especially for Disadvantages mass produced popular items). mass Expert Qualifications How Class Evidence may be turned into individual How evidence. evidence. Weight accorded by juries to scientific evidence Voir Dire - “speaking the truth” - challenging potential Voir jurors and expert witnesses’ qualifications jurors CHE 113 CHE 113 19 Disdvantages of Class Physical Evidence CHE 113 CHE 113 20 How Class Evidence may be turned into individual evidence. Conclusion of “Vinny” CHE 113 CHE 113 21 Physical Evidence ♦ Individual Characteristics - Properties of evidence that can connect a sample and standard to a common source (with high probability). e.g., fingerprints, unusual wear patterns, tool marks, etc. Body of a woman was found with a knife wound in her neck. A broken knife tip was found in the wound. The knife blade tip was compared with the knife found in the husbands pocket. Matches both in brake line and scratches. Saferstein Fig. 3.1 CHE 113 CHE 113 22 Individual Characteristics Firearms ID ♦ Properties of evidence that can be attributed to a common source with an extremely high degree of certainty ♦ Examples: bullets, knives, shattered headlight CHE 113 CHE 113 23 Physical Evidence CHE 113 CHE 113 24 Physical Evidence Lindberg Kidnapping Case CHE 113 25 Lindbergh Kidnapping ♦ Chas. A. Lindberg - first to fly solo across Atlantic (1927). ♦ One of the most famous Americans in the ‘20’s and ‘30’s. ♦ June 22, 1930, Chas. Lindberg Jr. born: Mar. 1, 1932 he was kidnapped. CHE 113 CHE 113 26 Lindbergh Case 9 p.m. on March 1, 1932 – ladder leaned on house and 20-month old son was kidnapped (Hopewell, NJ). Ransom note on window sill. CHE 113 CHE 113 27 Lindbergh Case Evidence found: •traces of mud were found on the floor of the nursery. •Footprints were found under the nursery window •Ladder •Ransom Note •no blood stains in the nursery, nor any fingerprints. •Household and estate employees were questioned and investigated. •Multiple other ransom notes bet’n Mar. 6th and 12th. •$50 ransom paid but no child delivered. •May 12th body of child found accidentally in woods. •Bruno Hauptman Arrested, Sept. 1934. CHE 113 CHE 113 28 Lindberg Kidnapping ♦ Ladder Used in Abduction CHE 113 CHE 113 29 Lindberg Kidnapping ♦ Ladder Used in Abduction CHE 113 CHE 113 30 Lindberg Kidnapping ♦ Ladder Used in Abduction CHE 113 CHE 113 31 Crime-Scene Reconstruction ♦ Collaborative effort of law ♦ ♦ ♦ ♦ enforcement personnel, medical examiners and criminalists Was there more than one person involved? How was the crime committed? Reconstruction supports likely sequence of events by the observation and evaluation of physical evidence and statements made by witnesses and those involved with the incident Reconstructions can play a vital role in aiding the jury to arrive at an appropriate verdict. CHE 113 CHE 113 32 Crime-Scene Reconstruction Step 1 - State problem - type of crime and the legal elements. Step 2 - Collect data - - records checks and police checks, interview victim, witnesses, and suspects, try to get additional witnesses and comparison samples from suspects Step 3 - Form a hypothesis - look at all evidence - determine Step motive and possible suspects motive Step 4 - Test hypotheses - evaluate how truthful and reliable the stories are, weigh their stories against the physical evidence the Step 5 - Follow up the most promising hypotheses (theories) Step 6 -- Draw conclusions - supported by court-admissible Step evidence leading to the arrest, prosecution, and conviction of the offender. CHE 113 CHE 113 33 Homicide: Rape: Robbery: 1- focus on deceased 1- focus on victim 2 -crime scene 2 - medical reports 3 - crime lab 3 - crime scene 4 - usual suspects Burglary: 1 - modus operandi 1 - focus on scene 2 - crime scene 2 - records check 3 - police records 3 - property check Source: adapted from Gilbert, J. (1980) Criminal Investigation. Columbus: Merrill. Patterns -- series of similarities that indicate the same person or the same modus operandi is involved in different crimes. or Leads -- clues or breaks in the case that move an investigation forward. forward. Tips -- provided by informants. Tips by definition involve specifics. specifics. Theories -- beliefs that point in one direction, at the exclusion of other possible directions. of Clues -- pieces of evidence that are consistent with the corpus delecti or elements of the crime. delecti CHE 113 CHE 113 34 Physical Evidence CHE 113 CHE 113 35 Crime-Scene Reconstruction Saferstein “Criminalistics” CHE 113 CHE 113 36 Kennedy Assassination PETER JENNINGS REPORTING: THE KENNEDY ASSASSINATION: BEYOND CONSPIRACY ABC News Special (Nov. 2003) http://www.youtube.com/watch?v=DSBXW1-VGmM CHE 113 CHE 113 37 End Chapter 3 CHE 113 CHE 113 38 ...
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This note was uploaded on 02/20/2012 for the course CHE 113 taught by Professor Spencer during the Spring '08 term at Syracuse.

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