U.S. flag

An official website of the United States government, Department of Justice.

What Every Law Enforcement Officer Should Know About DNA Evidence

Investigators and Evidence Technicians

Dry Stains on Non-absorbent Surfaces

Home  |  Glossary  |  Resources  |  Help  |  Contact Us  |  Course Map
 

Collection procedures for dry stains on non-absorbent surfaces are:

  • Submit the entire item if possible
  • If not, use the wet/dry swabbing technique
  • If unable to do either of the above, the scraping method also may be used. This is a method to be used in a controlled environment (i.e., no wind or traffic) and where the scrapings will not contaminate other evidence. This method is rarely used on scene. a new or clean scalpel blade or 3x5 index card to scrape the stains form the surface
  • Scrape the flakes onto clean, white paper and fold the paper properly (druggist fold/bindle)
  • Use a new or clean scalpel blade or 3x5 index card to scrape the stains form the surface
  • Scrape the flakes onto clean, white paper and fold the paper properly (druggist fold/bindle)
  • Place sample in a labeled envelope that provides reference information from where the sample was collected

Back Forward