Forensic Science

1. Unit 1 Forensic Science

2. Essential Question • What is Forensic Science?

3. Intro. to Forensic Science • Forensic Science – application of science to law

4. Essential Question • Who are some important people that have contributed to the field of forensic science? • What have these people contributed?

5. Sherlock Holmes • Fictional character developed by author Sir Arthur Conan Doyle • First to apply serology, fingerprinting, firearm identification, and questioned document examination • All of this – from fiction – before accepted by real-life criminal investigations.

6. Mathieu Orfila – 1813 • Father of Toxicology • Lafarge Trial (Marie) – arsenic • Book: Traite des poisons or Toxicologiegenerale – first scientific study of the detection and pathological effects of poisons – established toxicology as a distinct field of forensic science.

7. Alphonse Bertillon - 1879 • The father of criminal identification • Developed anthropometry – using body length measurements as unique properties – took 243 separate measurements • Method was coined “Bertillonage”

8. Francis Galton • Fingerprinting • Developed methodology for identification using the friction ridges on fingers • Basics still used today • His work has been enhanced by Sir Edward Henry – the father of modern fingerprinting • Henry developed a filing method for storing fingerprint patterns/records prior to computer storage capabilities • Wrote the book Fingerprints

9. Leone Lattes - 1915 • Blood testing – used technique developed by Dr. Karl Landsteiner • Bloodstains – developed method to determine blood type from dried blood • Discovered that blood typing could be used as a means of identification

10. Calvin Goddard – 1920s Father of Firearm Identification • Individualization of weapons • Firing pin marks on shell casings • Refined the technique of bullet comparison with the gun from which it was fired.

11. Albert S. Osborn • Handwriting expert – established the fundamental principles of document examination. • Wrote Questioned Documents

12. Hans Gross • First real life “scientific detective” – described the application of scientific disciplines to the field of criminal investigation. • Wrote first book on criminal investigation • Austrian lawyer • Coined the term “Criminalistics” • Wrote about: forensic medicine toxicology, serology, ballistics, and anthropometry • Suggested using: mineralogist, ecologist, and botanists

13. J. Edgar Hoover • Reorganized the Bureau of Investigations in 1924 • Included fingerprint cards • 1932 now FBI • Organized a national laboratory that aimed to offer forensic services of all law enforcement agencies

14. Edmond Locard Father of Forensics • Locard’s Exchange Principle – whenever two objects come in contact, material will be exchanged between them • Every criminal can be tied to crime by dust particles carried from the scene • Example: counterfeit coins – metal found in that matched those of the coins found on three suspects clothes – confronted with evidence – they confessed

15. Essential question • How are crime laboratories organized in the United States? • What units are present in most crime labs? • What is the responsibility of the units in each crime lab?

16. Organization • 5 main federal labs • Department of Justice (DOJ) labs at the Federal Bureau of Investigation (FBI) • United States Secret Service (USSS) • Department of Treasury labs at the Drug Enforcement Administration (DEA) • Bureau of Alcohol, Tobacco, and Firearms (ATF) • Postal Inspection Services (PIS) at the U.S. Postal Service (USPS)

17. Organization Cont. • Main lab in US is run by FBI and serves as a central repository for forensic info • Example • Integrated Fingerprinting Identification System (IAFIS) • Combined DNA Indexing System (CODIS) • Comparison standards for paint samples, tire patterns, bullets, explosives, and fibers, etc

18. USSS • Initially established to combat counterfeiting issues • Protected Grover Cleveland on part-time basis • Officially assigned to protect the president after the assassination of William McKinley • Maintains questioned documents lab • Analyze ink and paper to determine authenticity

19. DOJ lab at DEA • Analyze drugs for major components, determine side products, solvents, impurities, and starting ingredients • Determine geographical origin of illegal drug manufacturer • Allow monitoring of patterns of drug trafficking and development of illegal substances

20. ATF • Analyze physical evidence related to arson, explosives, firearms, tobacco, and alcohol • In conjunction with FBI developed National Integrated Ballistics Information Network (NIBIN)

21. PIS @ USPS • Mail crimes i.e. identify theft, mail fraud, letter bombs, child pornography • Can analyze envelope for location & criminal id • Sometimes DNA can be isolated from saliva

22. Units • Chemistry • Largest unit because most evidence is drug-related and 6th amendment guarantees right to speedy trial • gas chromatograph-mass spectrometer for drug analysis • Analyze trace evidence, explosives, metals, paints, minerals

23. Units (Cont.) • Physics • Crime scene reconstruction (car accident) • Reconstruct shooting • Biosciences • Analyze biological material for DNA i.e. blood, semen, saliva, skin, hair, etc • Identify biological samples • Toxicology • Analyze body fluids for presence of drugs or poisons

24. Units (Cont.) • Firearms • Comparison microscopy • Match markings left on cartridge cases by firing pin, breechblock, extractor, or ejector • Match test fired bullet • Fingerprints • Uncover latent prints by dusting, chemical, ultraviolet, and alternative light techniques • Photography • Record the crime scene

25. Units (Cont) • Questioned Documents • Forged, altered, counterfeit documents • Analyze ink, handwriting, printing, erasures obliterations, and charred documents • Evidence Collection • Trained evidence collection technicians travel to crime scene • Evidence Submission and Holding • Maintain chain of custody, secure evidence

26. Essential Question • What is the role of the forensic scientist? • What is the role of the crime scene investigator?

27. Forensic Scientists • Main job – analyze evidence • Train law enforcement (CSI) to identify, collect, and preserve evidence • Expert witness • Use physical evidence to connect the crime scene, the victim, and the criminal

28. Crime Scene Investigator • Recognize, collect, preserve evidence

29. Essential Question • What are different careers in Forensic Science?

30. Careers • Medical examiner • Physician authorized by state to investigate, unexpected, violent, suspicious, or unnatural deaths • Pathologist • Physician trained in determining cause of death; autopsy • Toxicologist • Detects presence of poisons or drugs in body fluids, tissues, and organs

31. Careers (Cont.) • Odontologist • Forensic dentists • Use dental records for id especially in burn victims • Forensic Psychiatrist • Apply psychiatry to law • develop profile and determine competency to stand trial

32. Careers (Cont.) • Forensic Engineer • Apply engineering principle to law • May determine structural failure such as bridge or building collapse • Forensic Anthropoloist • Performs specialized examination of human skeletal remains or badly decomposed bodies for id purposes • Forensic Entomologist • Apply study of insects to law

33. Essential Question • What is evidence? • What are the types of evidence? • What is the difference between individual and class evidence?

34. Evidence • Something that tends to establish or disprove a fact • Examples • Documents • Testimony • Other objects

35. Types of Evidence • Evidence • Testimonial • Expert • Eyewitness • Physical • Individual • Class

36. Expert Witness • Person who is a specialist in a subject • Only witness who can give their opinion

37. Eyewitness • Direct witness to an event • Reliability • Scene may have been too dark • Encounter may have been too brief • Presence of a weapon may have diverted the attention of the witness • Memory problems

38. Individual • Individualized to a single, specific source • No doubt as to what the source is • Fingerprints • DNA • Handwriting • Voiceprints • Always involves a comparison – an exemplar

39. Class Evidence • Consistent with a particular source • The more class evidence that fit the criminal – the better • Hair • Fibers • Soil • Glass fragments

40. Circumstantial Evidence • Much evidence is circumstantial • Implies a fact or event without actually proving it • Example • A blond hair is found in the hand of a murder victim with black hair • The more circumstantial evidence the greater the probative value

41. Essential Question • How can the probative value of class (identified) evidence be increased?

42. Class Evidence • Class evidence is used to narrow a suspect pool • The more class evidence found, the stronger the case against an individual

43. Probability and Class Evidence Scenario • A young person was seen leaving a high school parking lot after having been near a car with a broken window; the car’s CD player was missing. 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 1600 students, how common are these characteristics? *Note: The students do not wear uniforms.

44. Probability and Class Evidence • Suspect: • White t-shirt • Blue jeans • Light brown hair • Dark colored athletic shoes • Population size = 1600 • Sample is a typical classroom • Sample size = 33 students

45. Probability and Class Evidence • In the sample, 7 students are wearing white t-shirts, so we need to find the percentage of students in the class wearing white shirts. • 7 wearing a white shirt divided by 33 students in class = 0.21 or 21 % • So, how many students is 21% of the whole population? • 0.21 x 1600 = 336 students • Importance: Our suspect pool has just been narrowed from 1600 students to 336 students.

46. Probability and Class Evidence • How many students would be wearing blue jeans? In your class, you count 12 wearing blue jeans. • 12 wearing blue jeans divided by 33 students in class = 0.36, or 36% • How many students in the school would be expected to be wearing blue jeans? • 0.36 x 1600 = 576 students

47. Probability and Class Evidence • Next, determine how many students would be likely to have light brown hair. In your class, you count 5 students with light brown hair. • 5 with light brown hair divided by 33 students = 0.15 or 15% • How many students in school would be likely to have light brown hair? • 0.15 x 1600 = 240 students

48. Probability and Class Evidence • In your class, 4 students are wearing dark-colored athletic shoes. • 4 with dark-colored athletic shoes divided by 33 students = 0.12 or 12% • How many students in school would be likely to be wearing dark-colored athletic shoes? • 0.12 x 1600 = 190 students

49. Probability and Class Evidence • We have narrowed the pool four times, but the real power of this method is finding the probability of a person with all of these characteristics. • In order to do this, multiply the probability of each event together and then by the population size. • 0.21 x 0.36 x 0.15 x 0.12 x 1600 = 2

50. Probability and Class Evidence • Grand Finale • We have narrowed a pool of 1600 suspects down to two because we had four pieces of class evidence to consider. • Therefore, the probative value continues to grow by considering class evidence.