44.493 Issues in Criminal Justice and Technology

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• Serology
  serological specimens are among most often submitted types of evidence, but "crime lab generally will not analyze bloodstains unless a suspect has been identified. ..most labs find examination of bloodstains doesn't help when searching for suspect, but specimen can be preserved until and arrest, then analyzed."
• Toxicology
  Detects drugs, alcohol and poisons in the blood of suspects and victims. Also effective in testing questioned documents. NIJ grant, led to chromatography process to update process of dating inks.
• Anthropology
  can determine age, sex, race, stature, and even culture of a person simply by examining skeletal remains. Can tell which changes in body occurred before and after death, and can reconstruct the body's actual physical image.
• Tool Marks
  Have unique characteristics -- "signature" of tool that made them. 2 categories: impressions and striations. Impressions are usually found at the point of forced entry, while a striation is a scratch or gouge from tools scraping across other surfaces. Investigators preserve tool marks with photographs, or by recovering the item.
• Bite Marks
  "..can provide probable cause and lead investigators to arrest of a suspect." Classified by degrees. Goal: preserve them quickly because of body's rapid ability to heal. Can swab bite mark to detect secretor antigens for blood typing.
• Hair & Fibers
  can "tell investigators suspect's race, age, sex, and the part of the body from which it was taken...can reveal whether it was pulled out forcibly or fell out naturally, ismashed with a blunt object or sheared with a sharp instrument. Fibers..equally specific...vary dramatically in color, source, shape, and composition, ."
• Fingernails
  Nails are "unique to each individual ..rarely change throughout a person's life. Examined like tool marks and bullet casings, by finding identifying marks that link the suspect to the evidence."
• Glass
  "traces of blood, clothing, hair or fingerprints can be found on glass fragments..can establish ..presence at scene if matching fragments are found in clothing. ..can tell how crime was committed... studying conchoidal fractures, radial fractures and concentric breaks, can determine how glass was broken, angle ..bullet was fired, even which bullet was fired first through.. window with multiple bullet holes. "
• Impressions & Casts
  "..footprints can include or exclude suspects, and can show whether ..suspect was carrying a heavy object,.. walking or running, ..unfamiliar with area or unsure of tterrain. Tire marks show direction and approximate speed of travel, whether car leaked oil, transmission fluid or water..even manufacturer and the year tires made."
• Forensic Psychiatry
  Gives investigators "clues about a suspect's mental and emotional states, peculiarities, lifestyle and history, based on nothing more than the information found at the crime scene."

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