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Forensic Science

Forensic Science. Criminalistics Chapter 1: Introduction. What is Forensic Science?. The application of science and technology to those criminal and civil laws that are enforced by police agencies in a criminal justice system. Major Sciences Involved in Forensics. Chemistry:

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Forensic Science

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  1. Forensic Science Criminalistics Chapter 1: Introduction

  2. What is Forensic Science? The application of science and technology to those criminal and civil laws that are enforced by police agencies in a criminal justice system.

  3. Major Sciences Involved in Forensics • Chemistry: • examines the chemical makeup of substances found at the crime scene • Biology: • examines the biological properties of substances found at the crime scene

  4. Major Sciences Involved in Forensics • Physics: • examines the movement or impact of materials at the crime scene • Geology: • examines the earth’s components when important to the crime scene investigation

  5. History of Forensics • Sir Arthur Conan Doyle • Fictional character –Sherlock Holmes • The character, Sherlock Holmes, first applied these principles in Doyle’s novels: • Serology • Fingerprinting • Firearm Identification • Questioned-document examination

  6. History of Forensics • Mathieu Orfila (1787-1853) • Father of Forensic Toxicology • Spanish native—taught medicine in France • Published “The Detection of Poisons and Their Effects on Animals” which established Forensic Toxicology as a legitimate scientific endeavor

  7. History of Forensics • Alphonse Bertillon (1853-1914) • Father of Personal Identification or Criminal Identification • The science of anthropometry: a systematic method of taking body measurements • Anthropometry was eventually replaced by fingerprinting in the early 1900s

  8. History of Forensics • Francis Galton (1822-1911) • Studied fingerprints and developed a method of classifying them • Proved the uniqueness of individual fingerprints and their use for personal identification • His ideas describe the principles used today in fingerprinting

  9. History of Forensics • Leone Lattes (1887-1954) • Developed the concept that blood typing could be a useful identification tool in criminal investigation • Devised a simple procedure for determining the blood group from a dried blood stain

  10. History of Forensics • Calvin Goddard (1891-1955) • Colonel in the United States Army • First used the Comparison Microscope to determine if a bullet had been fired from a certain firearm • Established the Comparison Microscope as an indispensable tool in forensic investigations

  11. History of Forensics • Albert S. Osborn (1858-1946) • Development of the fundamental principles of document examination • Was responsible for the acceptance of document examinations as scientific evidence by courts of law • Authored “Questioned Documents” –a book still used in the field of document examination today

  12. History of Forensics • Walter McCrone (1916-2002) • Applied using microscopes to all fields of forensic investigations • Taught numerous forensic scientists how to use quantitative analysis methods in forensic investigations

  13. History of Forensics • Hans Gross (1847-1915) • Authored the first treatise describing the application of scientific disciplines to the field of criminal investigation • Detailed the assistance that investigators could expect from the numerous fields of science

  14. History of Forensics • Edmond Locard (1877-1966) • Strong advocate of the use of the scientific method in criminal investigation • Background in Medicine and in Law • Taught how scientific principles could be developed into a workable crime laboratory • Famous for Locard’s Exchange Principle

  15. Locard’s Exchange Principle The exchange of materials between two objects that occurs whenever two objects come into contact with one another

  16. Locard’s Exchange Principle • Examples: • Metal particles carried on clothing from a crime scene can link a suspect to a crime • Soil samples found on the vehicle of a suspect can link the suspect to a crime scene • Plant material found on cars or clothing can link a suspect to a crime scene

  17. Beginnings of Crime Labs • The oldest crime lab in the United States was established by the Los Angeles Police Department in 1923 under the Director August Vollmer

  18. The Federal Bureau of Investigation • 1932 • Director: J. Edgar Hoover • Organized a national crime laboratory to provide forensic services to all law enforcement agencies in the country

  19. The Federal Bureau of Investigation The FBI Laboratory is now the world’s largest forensic laboratory, performing over one million examinations per year

  20. The Federal Bureau of Investigation • Opened the Forensic Science Research and Training Centerin 1981 • Center is dedicated to conducting research and developing new and reliable scientific methods that can be applied to forensic science

  21. The Organization of a Crime Laboratory

  22. Crime Labs • Can be under the direction of … • The Police Department • The Prosecutors or District Attorney’s Office • The Coroner or Medical Examiner’s Office • Universities as independent testing facilities

  23. Crime Labs • Range in size and in the number of staff members • Can be classified under several jurisdictions • Federal • State • County • Municipal

  24. Crime Labs • There are approximately 320 public crime labs operating in various jurisdictions • These crime labs range being able to perform a diversity of tasks to very specialized scientific testing

  25. Growth of the Crime Lab • Some Reasons: • Courts placing greater emphasis on scientific evidence • Emphasis on thorough and complete police investigations • Increase in modern technology and types of testing that can be completed

  26. Growth of the Crime Lab • Major Reasons: • Increase in the crime rates in the United States • Even though many crimes do not require forensic evaluation of evidence

  27. Growth of the Crime Lab • Major Reasons: • The increased number of drug-related arrests • All seizures must be sent to the lab for confirmation of chemical composition of the substance • More drug arrests=Larger case loads of drug-related specimens

  28. Growth of the Crime Lab • Major Reasons: • The advent of DNA Profiling • Labor-intensive tests for DNA analysis • May come from blood evidence • May come from saliva or other bodily fluids • May come from bite marks, cigarette butts, hair, etc.

  29. Federal Crime Labs in the U.S. Will assist any local agency that requests assistance in investigative matters

  30. Federal Crime Labs in the U.S. • Federal Bureau of Investigation (FBI) • Housed under the Department of Justice • Responsibilities: • Broad, investigative powers that exceed jurisdictions of state and local authorities • Expertise and technology support for criminal investigations

  31. Federal Crime Labs in the U.S. • Drug Enforcement Agency (DEA) • Housed under The Department of Justice • Responsibilities • Analysis of drugs seized in violation of federal laws that regulate the production, sale, and transportation of drugs in the U.S.

  32. Federal Crime Labs in the U.S. • Bureau of Alcohol, Tobacco, Firearms, and Explosives (ATF) • Housed under The Department of Justice • Responsibilities: • Analyzing alcoholic beverages and documents relating to tax law enforcement • Examining weapons, explosive devices, and evidence relating to the Gun Control Act of 1968 and the Organized Crime Control Act of 1970

  33. Federal Crime Labs in the U.S. • U.S. Postal Inspection Services • Housed under The Department of Justice • Responsibilities: • Investigates criminal acts relating to the postal service

  34. State Crime Labs in the U.S. Most states have crime labs to assist local law enforcement agencies that do not have easy access to a crime lab

  35. State Crime Labs in the U.S. Some states, such as Alabama, have developed a comprehensive statewide system of crime labs with satellite facilities Maximizes access to lab services without duplicating services at each site Sharing of expertise and equipment

  36. Services of the Crime Lab

  37. Variation in Services • There are many different services available in different crime labs • Reasons: • Variations in local laws • Different capabilities and functions of the organization in which the lab is attached • Budgetary and staffing limitations

  38. Full-Service Crime Lab: 5 Parts • Physical Science Unit • Applies the principles and techniques of chemistry, physics, and geology to identification and comparison of crime-scene evidence • Examples: • Drug Chemistry Identification • Soil/Mineral Analysis • Physical Properties of Trace Evidence

  39. Full-Service Crime Lab: 5 Parts • Biology Unit • Staffed with biologists and biochemists that apply their knowledge to the identification of biological aspects of a crime scene • Examples: • Identification and DNA profiling of dried blood stains and other bodily fluids • Hair and fiber comparison • Identification of plant material

  40. Full-Service Crime Lab: 5 Parts • Firearms Unit • Responsible for the examination of firearms, discharged bullets, cartridge cases, shotgun shells, and ammunition of all types • Examples: • Examination of ammunition casings • Firearm or gunpowder residue • Target length • Toolmarks

  41. Full-Service Crime Lab: 5 Parts • Document Examination Unit • Studies the typewriting and handwriting on questioned documents to determine authenticity and/or source • Examples: • Handwriting identification • Analysis of ink or paper • Indentations • Erasure marks

  42. Full-Service Crime Lab: 5 Parts • Photography Unit • Used to examine and record physical evidence • Examples: • Digital imaging • Infrared imaging • Ultraviolet imaging • X-ray photography

  43. Crime Lab Optional Services • Toxicology Unit: • Determines the presence or absence of drugs or poisons • Latent Fingerprint Unit • Processes and examines evidence for latent fingerprints • Polygraph Unit • Administers lie detector tests to suspects

  44. Crime Lab Optional Services • Voiceprint Analysis Unit • Analyzes tape-recorded messages or telephoned threats • Evidence Collection Unit • Collects and preserves evidence at the crime scene

  45. The Functions of the Forensic Scientist

  46. Forensic Scientists Must be skilled in applying the principles and techniques of the physical and natural sciences to the analysis of many types of evidence that may be recovered at a crime scene

  47. Forensic Scientists Must have a firm, scientific foundation and follow specific procedures in order for evidence to be admissible in court

  48. Frye v. United States • Court case that established what type of rules scientific evidence have to follow • Said that scientific procedures will only be allowed in a court of law if the procedures used are “generally accepted by the scientific community” • Helps establish the accuracy and validity of the tests and the results easy to understand by all scientists

  49. “Generally Accepted Procedures” • How are “generally accepted procedures” determined? • Expert witnesses • Books • Documented studies • Case history

  50. Daubert v. Merrell Dow Pharmaceutical, Inc. • Court case in 1993 • Asserted that “general acceptance” is not an absolute prerequisite for admissibility • The judge in the case can be a “gatekeeper” in deciding the admissibility and reliability of scientific evidence that is presented in a courtroom

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