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Technical Working Group on Biological Evidence Preservation

Contact: Melissa Taylor, 301-975-6363

The Importance of Preserving Biological Evidence

Forensic DNA analysis has had an enormous impact on the criminal justice system since its introduction into the court system in the late 1980s. Property and evidence rooms are tasked with the daunting responsibility to maintain the integrity of biological evidence and to ensure that it is properly stored, tracked, and disposed of. The 2009 National Research Council's report, Strengthening Forensic Science in the United States: A Path Forward, highlights that, "In order for qualified forensic science experts to testify competently about forensic evidence, they must first find the evidence in a usable state and properly preserve it." In August 2009, NIST and the National Institute of Justice convened the first meeting of Technical Working Group on Biological Evidence Preservation to offer guidance to evidence custodians who have been traditionally plagued by a lack guidance on how to properly store biological evidence after collection and through post-conviction.





Working Group Charge

The Technical Working on Biological Evidence Preservation is charged to create best practices and guidance to ensure the integrity, prevent the loss, and reduce the premature destruction of biological evidence after collection through post-conviction proceedings. Biological evidence refers to samples of biological material -- hair, tissue, bones, teeth, blood, semen, or other bodily fluids -- or evidence items containing biological material.

The Biological Evidence Preservation Handbook: Best Practices for Evidence Handlers contains recommendations on the retention, packaging, tracking and disposition of biological evidence, as well as guidance outlined below.

Short and Long Term Biological Evidence Storage Conditions
Applicable definitions and supporting research for the tables below can be found in The Biological Evidence Preservation Handbook.

Short-Term Storage Conditions

Short-Term BioEv Storage Matrix

Long-Term Storage Conditions

Long-Term BioEv Storage Matrix

Considerations for Storage of Bulky Evidence

 BioEvCouch v2

For the long term, agencies might find it sufficient to retain samples taken from a large item (see B. and C. in the above figure) as opposed to the large item on which biological evidence may have been located (see A.). If the origin of a sample is well documented (such as through photographs or case files), it may not be necessary to store the large item for testing and future re-testing.

Appropriate Packaging Equipment, Materials, and Guidelines

BioEv CommercialDryer

BioEv SAkits

BioEv CommercialFridge


Resource Library

The Technical Working Group on Biological Evidence Preservation created the following images and documents to fulfill its charge.



Other Related Resources

Packaging and Collection Guidance

There are extensive references on proper collection and packaging practices. Examples include:

Other related references can be found at the websites below:

Training Resources

Evidence custodians can obtain training at the websites below:

Property and Evidence Associations

International Association

State Associations

Biohazard Disposal Guidelines