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Trace Evidence

Trace evidence consists of very small particles that are left behind when two objects touch. This evidence can be used to associate items and to identify suspects through their clothing, hair, or other materials.

  • Fibers
  • Glass
  • Hair
  • Paint
  • Tape

Specific Projects

Refractive Index Glass Standard Reference Material
We are working with other areas of NIST to replenish the depleted NIST Standard Reference Material (SRM) stock, which is utilized by forensic laboratories that conduct glass analysis. These laboratories must use traceable reference materials when analyzing forensic evidence to meet quality assurance and accreditation requirements. The depletion of the NIST glass refractive index SRM caused some laboratories to seek other options to meet accreditation requirements. Therefore, the forensic community needs a new glass refractive index SRM.

To ensure glass is clear and transparent, it is specially treated to maximize the ability of light rays to pass through in a single direction. With NIST, we have measured the refraction of glass prism samples to a 5-decimal-place index of refraction values. Next, we will begin measuring the glass density. When these measurements are completed, the standard reference material will be available on the SRM page.

Broken Glass

Additional Resources

There are several Scientific Working Groups that provide information related to trace evidence, such as: