Intro to Forensic Science


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Intro to Forensic Science

  1. 1. Introduction
  2. 2.  The science that is applied to the law and criminal proceedings. It applies the knowledge and technology of science for the definition and enforcement of criminal and civil law. Often referred to as criminalisticsWhat is forensic science?
  3. 3.  They have the ability to supply accurate and objective information that reflects the events that have occurred at a crime.Why is the forensic scientist soimportant to the justice system?
  4. 4.  NO!!! Possible needs include: ◦ Burglary ◦ Counterfeiting/art forgery/document forgery ◦ White collar crime (embezzlement, etc.) ◦ Computer crime ◦ Auto accident ◦ Arson ◦ Drug enforcement ◦ Terrorism ◦ ETC….Is Forensic Science only applied tocases involving homicides?
  5. 5.  Crime labs are not typical to one type of model because they can vary in: ◦ Size ◦ # of employees ◦ Who runs them (ex: police department, prosecutor/D.A.’s office, universities, or independent agencies in the government) ◦ Services they provide Currently there are over 320 public crime labsOrganization of a Crime Lab
  6. 6.  A typical crime lab has two sets of personnel: ◦ Field analysts - investigators that go to crime scenes, collect evidence, and process the scene. ◦ Laboratory analysts - scientists or other personnel who run tests on the evidence once it is brought to the lab (i.e., DNA tests, or bullet striations).Organization of a Crime Lab
  7. 7.  In the United States, crime labs may be publicly or privately operated, although private laboratories typically do not respond to crime scenes to collect evidence. Public crime labs are organized at the city, county, state, or national level.Organization of a Crime Lab
  8. 8.  The federal government has no single law enforcement or investigative agency that has unlimited jurisdiction. 4 major federal crime labs have been created that extend beyond the jurisdictional boundaries of state and local forces.Organization of a Crime Lab
  9. 9.  1. FBI –maintains the world’s largest crime lab 2. Drug Enforcement Administration Labs (DEA) – responsile for analysis of drugs seized in violation of federal laws 3. Bureau of Alcohol, Tobacco, and Firearms – responsible for analyzing alcoholic beverages and documents relating to tax law enforcement 4. U.S. Postal Inspection Service – concerned with criminal investigations relating to the postal serviceFederal Crime Labs
  10. 10.  Physical Science Unit ◦ Applies principles and techniques of chemistry, physics, and geology. ◦ Examination of items as diverse as drugs, glass, paint, explosives, and soil. Biology Unit ◦ Staffed with biologists and biochemists for DNA profiling of dried bloodstains and other bodily fluids, comparison of hair and fibers, & identification and comparison of botanical materials such as wood and plantsBasic Services
  11. 11.  Firearms Unit ◦ Examination of firearms, discharged bullets, cartridge cases, shotgun shells, and ammunition of all types is conducted ◦ Garments and other objects are also examined in order to detect firearm discharge residues Document Examination Unit ◦ Handwriting and typewriting on questioned documents are studied to ascertain authenticity and/or source. ◦ Analysis of paper and inkBasic Services
  12. 12.  Photography Unit ◦ Examine and record physical evidence ◦ Use of digital imaging, infrared, ultraviolet, and X-ray photography, to make invisible information visible to the naked eye.Basic Services
  13. 13.  Toxicology Unit ◦ Body fluids and organs are examined to determine the presence/absence of drugs and poisons Latent Fingerprint Unit ◦ Processing and examining evidence for latent fingerprints Polygraph Unit ◦ Lie detector ◦ Essential tool of the criminal investigatorOptional Services
  14. 14.  Voiceprint Analysis Unit ◦ Used for cases involving telephoned threats or tape-recorded messages to tie the voice to a particular suspect. Evidence-Collection Unit ◦ Dispatches specially trained personnel (civilian and/or police) to the crime scene to collect and preserve physical evidence.Optional Services
  15. 15.  The role of the forensic scientist is twofold: ◦ to analyze physical evidence found on a victim on the scene of a crime and ◦ compare it to evidence found on a suspect and to provide expert testimony in a court of law.Role of the Forensic Scientist
  16. 16.  Because their work product may ultimately be a factor in determining a person’s guilt or innocence, forensic scientists may be required to testify with respect to their methods and conclusions at a trial or hearing. In this case, they are considered an expert witness (an individual whom the court determines possesses knowledge relevant to the trial that is not expected of the average layperson.Role of the Forensic Scientist
  17. 17.  Forensic Pathology ◦ Involves the investigation of sudden, unnatural, unexplained, or violent deaths. ◦ If a cause cannot be found through observation, an autopsy is normally performed to establish the cause of death.Additional Forensic Services
  18. 18.  After a human body expires, it goes through several stags of decomposition. Stages of Death: ◦ Rigor Mortis – shortening of muscle tissue and stiffening of body parts in the position they are in when death occurs  Manifests within the first 24 hours and disappears before 36 hours ◦ Livor Mortis – settling of blood in areas of the body closest to the ground  Early stages of decomposition  Due to the heart stop pumping ◦ Algor Mortis – body temperature continually cools after death until it reaches the ambient of room temperature  Rate of heat loss due to location, body size, victim’s clothing, and weather conditions  Heat loss: 1-1.5°F / hourForensic Pathology
  19. 19.  Another helpful method to determine time of death is to determine potassium levels in ocular fluid (vitreous humor) After death cells within the inner surface release potassium into the vitreous humor (this rate approximates the T.O.D.)Forensic Pathology
  20. 20.  Concerned primarily with the identification and examination of human skeletal remains An examination of bones can reveal origin, sex, approximate age, race, and skeletal injury. Also assist in creating facial reconstructions to aid in the i.d. of skeletal remains or mass disasters (i.e. plane crash)Forensic Anthropology
  21. 21.  The study of insects and their relation to a criminal investigation. Used to estimate the time of deathForensic Entomology
  22. 22.  Specialized area in which the relationship between human behavior and legal proceedings is examined Retained for both civil and criminal litigationsForensic Psychiatry
  23. 23.  Provide information for the identification of victims when the body is left in an unrecognizable state Teeth are composed of enamel, the hardest substance within the body and therefore have a resilience that will outlast tissues and organs as decomposition begins Also used in bite mark analysis (i.e. case of Ted Bundy)Forensic Odontology
  24. 24.  Concerned with failure analysis, accident reconstruction, and causes and origins of fires or explosionsForensic Engineering