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Collecting DNA Evidence at Property Crime Scenes

Biological Evidence Packaging

Biological Evidence Packaging

The general procedure for packaging biological evidence is as follows:

  • Use clean dry implements.
  • Label all metal and glass items collected for "Room Temperature Storage," as cold or frozen storage causes condensation on these surfaces, which may dilute biological evidence.
  • Air-dry swabs as soon as possible after collection.
  • Package all swabs individually in separate containers.
  • Store all swabs as soon as possible per agency protocol.
  • Do NOT use double-tipped swabs.
  • Label as biohazard.

Anytime you transfer material for collection, you create the chance of diluting or contaminating your evidence. All evidence recovered at a crime scene, or received at or during a crime scene investigation, should be inventoried and packaged to prevent cross-contamination prior to leaving the scene. The package should be marked, as well as the item of evidence, if possible.

Remember that wet and dried evidence should not be folded over on itself. The video below shows the use of paper wrapping to prevent contamination during the packaging process to separate and wrap the item. This will protect bloodstain patterns and prevent cross-contamination between stains on one item.

Placing a laboratory tag on or directly marking certain items of evidence is not always possible due to the type of item, or the condition. Marking an item directly may possibly interfere with subsequent forensic analysis of the item.

Evidence which cannot be tagged, such as soil, hair and stains, should be placed in an appropriate container or envelope. The packaging container should be tagged. The tag should be completed with the following information:

  • Agency case number.
  • Item number.
  • Date recovered or received.
  • Investigator's initials.

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