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What Every Law Enforcement Officer Should Know About DNA Evidence

Investigators and Evidence Technicians

Procedures for Sexual Assault Evidence

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Procedures for Collecting Sexual Assault Evidence

Image of evidence collection including blood on fabric stored in paper
National Institute of Justice (NIJ) (see reuse policy).
  • If the victim was forced to perform oral sex, the victim's mouth should be swabbed. The swab should be air-dried and packaged in a labeled paper or glassine envelope.
  • If the victim was licked, kissed, or sucked on any part of the body, the area should be wet/dry swabbed (wet swab moistened with distilled water) to recover residue saliva using new sterile swabs. Air-dry swabs and package them separately in labeled envelopes. Packaging should document exact locations with reference points indicating what area was swabbed.
  • Seminal or vaginal stains on undergarments (victim or suspect), clothing (victim or suspect), bed sheets, and pillows should be collected as evidence
  • Garments thought to contain vaginal or seminal stains should be air-dried, wrapped, and packaged in paper to prevent cross-contamination of evidence
  • If clothing, garments, or bed linens must be folded for collection, place paper between each fold to prevent the inadvertent transfer of evidence
  • Lubricants, such as creams, oils, and/or petroleum jellies, should be submitted in original containers

Note: It may be necessary to collect evidence from a suspect. Pubic hair combings and scrotal or penile swabbings can be evaluated for DNA evidence.

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