Chapter_1.ppt
- 1. Introduction to Forensic Science Chapter 1
- 2. Chapter 1 Objectives • To be able to define forensic science and describe its various areas • To be able to describe the major events in the history of forensic science and relate them to modern-day practice • To be able to describe the duties of a forensic scientist
- 3. • To be able to describe the organization of federal, state, and local forensic science laboratories • To be able to diagram and describe the flow of evidence through a crime laboratory • To be able to describe the qualifications for becoming a forensic scientist • To be able to get information on careers in forensic science
- 4. FORENSICS • Today we use the term to mean the methods of science applied to matters involving the justice system • Which sciences are forensic sciences? – Any science can be a forensic science if it has some application to justice – Criminalistics, Pathology, Anthropology, Odontology, Engineering, Entomology
- 5. CRIMINALISTICS • The term can be used to describe the comparative forensic sciences such as fingerprints, questioned documents, firearms and toolmarks • Most commonly, however, criminalistics refers to the myriad of types of physical evidence generated by crime scenes – Illicit drugs, blood and DNA, fire and explosive residues, hairs and fibers, glass and soil particles, paints and plastics, fingerprints, bullets, and much more
- 7. PATHOLOGY • Forensic pathologists determine the cause and manner of death in cases where someone dies under suspicious circumstances • Cause of death – event that directly causes death – Stroke, drug overdose, auto crash, poisioning, etc. • Manner of death – the type of death (four only) – Homicide, natural, accidental, and suicide • Autopsy (or postmortem examination) is used to make these determinations • Pathologists work for medical examiners or coroners (varies by state)
- 9. ANTHROPOLOGY • Forensic anthropologists work with skeletal remains • If human, they determine from what part of the body the bone originated • If they have the correct bones: – Gender, age, racial characteristics, and even socioeconomic status can be determined • If there is an injury to a skeleton or major bones, the cause of the injury or death can be determined • It is also possible to build a face onto a skull using clay and pegs of various sizes • Facial reconstruction helps find missing persons
- 11. ODONTOLOGY • Odontology is a fancy name for dentistry • Bite marks on a victim or other object can be matched to a suspect • Forensic odontologists can also help identify remains from disasters such as plane crashes – Postmortem dental records are taken and matched to x-rays taken before death • It is also possible to distinguish causes of facial injuries – Falling down the stairs vs. being struck by an object
- 13. ENGINEERING • Forensic engineers can be valuable in cases where something has gone wrong with a mechanical or structural entity or in cases of automobile crashes • Failure analysis is one of the major contributions that forensic engineers make to the justice system • The majority of the work of forensic engineers is in the investigation of traffic crashes – Accident reconstruction is used to determine speeds, directions of impact, and who was driving the vehicle at the time of impact
- 15. ENTOMOLOGY • Flies (usually blowflies) are usually the first to arrive at a crime scene • Flies and other insects lay their eggs in decaying flesh – Different insects do this at different times – Other insects such as beetles and wasps will attack and feed off the insects and eggs • This parade of visitors takes place at surprisingly consistent time intervals • Forensic entomologists can estimate the postmortem interval (how long ago death occurred) • If a person has been poisoned or has overdosed, flies and other insects will ingest this as well
- 17. Who Are Forensic Scientists? • Two types: – Enlisted (sworn police officers) – Civilian • As forensic science became more technical, civilians were hired because it became difficult to recruit scientists to be police officers • Forensic scientists have very little function in evidence collection and rarely attend crime scenes • Forensic scientists have two main duties: – To analyze evidence – To testify in court
- 19. Testifying In Court • Lay witnesses testify as to what they have perceived with their five senses – They are not to give their opinions! • Expert witnesses have knowledge or skills from education or experience that qualify them to give opinions and draw conclusions • The judge decides if expert testimony is needed and who is qualified to offer it
- 21. The U.S. Forensic Science System • There are about 400 forensic science laboratories in the U.S. • Most federal crime labs are in the Department of Justice under the control of the attorney general • The FBI is know for having some of the most prestigious forensic science laboratories in the world • The DEA has labs that analyze seized illicit drugs • The secret service has labs to prevent harm to protected people and to prevent counterfeiting and credit card fraud
- 22. The U.S. Forensic Science System (2) • The Department of the treasury has crime labs • The BATF labs have some of the world’s leading experts in fire and explosive analysis • IRS crime labs specialize in the area of questioned documents – handwriting, typewriting and printers, inks, and papers • The Dept. of the Interior has crime lab to investigate poaching and hunting • Each of the 50 states has a public crime lab system and most have locally controlled facilities
- 24. Private Forensic Crime Laboratories • Private labs usually work for the defendants – Only the prosecutor has access to the local or state public laboratory •The private labs perform a service to the criminal justice system by providing resources for those accused of crimes
- 25. Organization of Forensics Labs • Typical forensic science labs have – An intake section – Analysis areas – Other sections
- 26. INTAKE SECTION • An intake officer logs evidence into LIMS and affixes a barcode (Laboratory Information System) • Chain of custody for physical evidence must be authenticated – There must be proof that the evidence seized at a crime scene is the same evidence that appears in court – An improper chain of custody can be grounds to render evidence inadmissible • Considerations are made before testing so that one test does not ruin the conditions for another – A gun may need to be test fired, fingerprinted, and have blood removed. The order is important!
- 28. ANALYSIS AREA • This is the familiar laboratory setting • Each scientist will have a designated area of the lab for evidence handling • There are lots of instruments, glassware, implements, and scientists in white lab coats and safety glasses
- 30. OTHER LAB SECTIONS • Some labs may have a garage where cars can be kept for inspection and searching • Many firearms sections have huge stainless steel tanks that are full of water – These are used to test-fire weapons for comparison with bullets or cartridges from crime scenes • Some large labs have collections of seized weapons as well as ammunition • There may also be interrogation rooms where polygraph tests are performed
- 32. CAREERS • Becoming a forensic scientist requires education and training – Crime lab forensic scientist – Forensic pathologist – Forensic anthropologist – Forensic odontologist – Forensic Engineer
- 33. Crime Lab Forensic Scientist • Entry level requirements include a bachelor’s degree in chemistry, biology, or forensic science and 1-2 years of experience or a master’s degree with less experience • The job market is very competitive and a master’s degree is preferred
- 34. Forensic Pathologist • Graduate from college with an excellent academic record (4 years) • Graduate from medical school (4 years) • Complete a residence in pathology (4 years) • Complete a residency in forensic pathology (1 year)
- 35. Forensic Anthropologist • Few crime labs can afford to hire a full-time forensic anthropologist • A lab may hire you full time if you have another specialty (trace evidence, DNA typing, etc.) • Most obtain a Ph.D. and teach at a university and handle cases part-time
- 36. Forensic Odontologist • This is similar to the route for a forensic pathologist except that you would complete dental school instead of medical school • There are very few residencies in forensic odontology • You would need to work with the police on an as-needed basis
- 37. Forensic Engineer • Require an education in engineering (the more the better) • Usually, Ph.D.s are in demand • Most forensic engineers have their own companies that are hired by prosecutors or defendants