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Trace Evidence FAQ

  • Why can't I submit debris from a fire scene in a plastic or paper bag?

  • Many petroleum products, or other potential accelerants, evaporate very quickly. An airtight container must be used to ensure that any product is retained in the debris rather than lost prior to analysis. We recommend clean, lined, airtight paint cans as the most appropriate containers for fire debris.

  • Will the laboratory analyze fireworks?

  • If an item is commercially labeled D.O.T. Class C. Fireworks, it is not necessary for the laboratory to analyze the chemical content of the item. The Code of Virginia lists those fireworks that are “legal” and the remainder are excluded based upon their function not chemical composition. Oftentimes a videotape of the device being set off is sufficient for court. See Code of Virginia Sections §59.1-142 and §59.1-147.

  • What is the submission criteria for primer residue kits ?

  • Requests for Primer Residue (PR) examinations of samples obtained from living persons suspected of firing a weapon will be routinely accepted.  Primer Residue kits collected from the following will not be routinely accepted: gunshot victims, inanimate objects, and individuals found in possession of a weapon.  There is no need to submit a CA letter with the submission of any PR case.   New submission guidelines are posted on our website: https://dfs.virginia.gov/wp-content/uploads/2016/06/Trace-Policy-Change.pdf

  • Why is a moist towelette provided with primer residue collection kits?

  • The towelette is provided for collecting officers to wipe their hands with before using the kit to sample a subject’s hands for primer residue.  Washing the hands or wearing gloves is also an option if available.  These precautions are the best way to ensure that the collecting officer is not a source of contamination on samples collected from the subject’s hands.

  • What is the best time and place to collect a primer residue sample?

  • It is best to collect at the scene or as soon as possible.  Kits collected from living individuals beyond 8 hours after an incident will not be accepted for analysis.  If the subject must be transported before being sampled, bag the hands with paper or Tyvek® bags to prevent contamination and loss of particulate.

  • What is the procedure for getting primer residue collection kits for my agency?

  • Primer residue kits are available from the Evidence Receiving Sections at each of the four DFS laboratories.

     Central Lab - Richmond

    Eastern Lab - Norfolk

    Northern Lab - Manassas

    Western Lab - Roanoke