FIBERS

Trace Evidence

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Physical Properties

  • Texture
  • Length
  • Color
  • Shape

Chemical Properties

Absorbency

  • its ability to take in moisture
  • moisture regain


Wicking

  • ability to carry its moisture along its surface


Electrical Conductivity

  • Fibers that do NOT conduct electricity create
  • Static electricity


Chemical Reactivity

  • How it reacts to chemicals such as dyes, pigments,
  • Soaps, detergents and bleaches

How Scientists Analyze Evidence

Fibers are very important because they can determine what the suspect was wearing and what kind of fabric it is to possibly trace it to the suspect. They have people with special suits so that their clothes or hair wouldn't mix with the evidence.
NC Science Olympiad: How to do a Fiber Burn Test
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Case Involving Fibers

Dr. Jeffrey MacDonald, Army captain was accused of murdering his pregnant wife and two children in 1970. The investigators were suspicious of the doctor because of the nature of his wounds suggesting that they were not defensive and perhaps even self inflicted. Blue threads that matched the doctor’s pajama top were found under the body of his wife as well as in the bedroom of both murdered children and even under the fingernails of one of his daughters. When MacDonald was confronted with this and other evidence he reportedly stated “You guys are more thorough than I thought”

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