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 Forensic Science: A Definition
• Application of science to law
• Applies the knowledge and technology of
  science for the definition and enforcement
  of such laws.
   Forensic science is the application of science to
   those criminal and civil laws that are enforced
   by police agencies in a criminal justice system.
History and Development
     1814                   1879

    Mathieu Orfila:      Alphonse Bertillon:
    Father of Forensic   developed the
    toxicology           science of

       1892                  1929
                            Calvin Goddard:
    Francis Galton:         developed the
    first study of          comparison
    fingerprints            microscope for
  …more History
          1910                 1950’s

         Principles of       Microscopy as a
         document            tool for the
         examination         forensic scientist

  1893                     1910

Developed the            Locard’s Exchange
application of           Principle
principles to
 Organization of the Crime Lab
• 320 public crime labs in the U.S…a tripling
  of the number since 1966.
• Supreme Court decision Miranda v.
  Arizona (1966)
• Increase in drug abuse
• Advent of DNA profiling
• Most State Governments maintain crime
  labs plus satellite labs.
     Services of the Crime Lab
• Physical Science Unit   •   Toxicology Unit
• Biology Unit            •   Latent Fingerprint Unit
• Firearms Unit           •   Polygraph Unit
• Document Examination    •   Voiceprint Analysis unit
• Photography Unit        •   Evidence Collection Unit
       Physical Science Unit
• Chemists, physicists and geologists
• Items such as drugs, glass, paint,
  explosives and soil are identified
• Analytical and chemical analysis
              Biology Unit
• Biologists and biochemists
• Identification and DNA profiling of dried
  blood stains, other body fluids, comparison
  of hairs and fibers
• Identification and comparison of botanical
  materials such as wood and plants.
            Firearms Unit
• Examination of firearms, discharged
  bullets, cartridge cases, shotgun shells
• Examination of garments to detect firearm
  discharge residue to approximate distance
  from target when weapon was fired.
   Document Examination Unit
• Handwriting and typewriting (word
  processing) analysis to determine
  authenticity and/or source
• Analysis of paper and ink and indented
  writings (impressions)
• Obliterations, erasures and burned or
  charred documents
          Photography Unit
• Examine and record physical evidence at
  the scene
• Digital imaging, IR, UV, and X ray
  photography to make invisible information
  visible to the naked eye
• Preparation of photographic exhibits for
  courtroom presentation.
           Toxicology Unit
• Body fluids and organs for the presence or
  absence of drugs and poisons.
• Works with the coroner or medical
  examiner’s office
• Blood alcohol content
       Latent fingerprint Unit
• Processing and examining prints to
  determine possible matches with victims
  and suspects
            Polygraph Unit
• Used in conjunction with interrogation to
  determine credibility of suspects and
            Voiceprint Unit
• Interpretation of telephone threats
• Tape recorded messages
• Tie the voice to a suspect
     Evidence Collection Unit
• CSI: trained personnel who are
  dispatched to the crime scene to collect
  and preserve physical evidence
Functions of the Forensic Scientist
• Frye v. United States: 1923 Rejection of Lie
  Detector (Polygraph) results necessitated
  guidelines for determining judicial admissibility of
  scientific examinations.
• The Frye Standard: The court must decide if the
  questioned procedure, technique or principles
  are “generally accepted” by a meaningful
  segment of the scientific community.
• Expert testimony challenged: Daubert v. Merrell
  Down Pharmaceutical. Trial judge is the
  ultimate determined in admissibility.
           Daubert v. Merrel
• Whether the scientific technique or theory can
  be tested.
• Whether the technique or theory has been
  subject to peer review and publication.
• The technique’s potential for error.
• Existence and maintenance of standards
  controlling the technique’s operation.
• Whether the scientific theory or method has
  attracted widespread acceptance within a
  relevant scientific community.
            Coppolino v. State
• M.E. testified that victim died of an overdose of a drug
  called succinylcholine chloride based on his toxicology
• Succinylcholine chloride breaks down into succinic acid
  in the body.
• This drug had never before been detected in a human
• Defense argued that this test was new and absence of
  corroborative experimental data by other scientists.
• The court rejected the defense’s argument on the
  grounds that although the tests may be new and unique,
  they are admissible only if they are based on
  scientifically valid principles and techniques.
          Expert Testimony
• Must be competent: education degrees,
  member of applicable societies, published
  papers or books,etc.
• Defense may cross-examine the potential
  expert witness.
• The individual trial judge is the ultimate
  decision maker regarding expert
Training in Recognition, Collection,
  and Preservation of Evidence
• Specially trained evidence collectors: CSI
• On 24-hour call to aid criminal
  investigators in retrieving evidence
• Specially equipped with all the proper
  evidence collection equipment
• Unfortunately, some police forces still
  don’t use them or the police themselves
  have contaminated the crime scene before
  the CSI team gets there!
            Forensic Pathology
• Investigation of sudden, unnatural, unexplained, or
  violent death.
• Medical Examiner vs Coroner = M.D. vs political
• Autopsy:
• Causes of death: natural, homicide, suicide, accident,
• Rigor mortis: starts within the first 24 hours and
  disappears after 36 hours. Helpful in estimating time of
  death. See “Algor mortis”
• Livor mortis: settling of blood after the heart stops. Skin
  appears dark blue. Used to determine position of body
  at time of death.
     Determining time of Death
• Algor mortis: continual cooling of body
  temperature after death
• Factors: location of body, size of body, victim’s
  clothing, ambient temperature
• General Rule: Beginning about an hour after
  death, the body will lose heat at a rate of 1 to 1.5
  degrees F. per hour until the body reaches the
  environmental temperature.
• Potassium levels in the vitreous humor of the
    More time of death factors
• Food in victim’s stomach can establish the
  time the victim last ate.
• Liver temperature if done at the crime
• Anal temperature compared to ambient
Other Areas involving Forensics
• Anthropology: Examination of human skeletal
• Entomology: insect life span can be used to
  determine the time of death.
• Psychiatry: competency of suspect; serial killed
• Odontology: body identification based on dental
  records; evidence using bite marks left on
• Engineering: accident reconstruction to
  determine causes