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What Every Law Enforcement Officer Should Know About DNA Evidence

First Responding Officers

Preventing Contamination

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Images of evidence contamination including touching the face, sneezing, touching an area where DNA might exist overlaid with a red do not do symbol
National Institute of Justice (NIJ) (see reuse policy).

This is a list of actions to avoid in order to prevent contamination at the crime scene.

  • Do not touch the area where you believe DNA exists.
  • Do not touch your face, nose, hair and mouth when collecting and packaging evidence.
  • Do not sneeze or cough near evidence. If you are prone to coughing or sneezing, a face mask should be worn.

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