Five Things About Sexual Assault Kits

Investments in research have dramatically improved the science of forensic DNA testing and our understanding of sexual assault kits. Here are Five Things we know and don’t yet know, based on research to date:

1. No one knows the number of kits nationwide that have not been submitted for testing.

Most kits that have not been tested are in police custody, not in crime labs. There is no national estimate of these unsubmitted kits. One first step to knowing the number and nature of unsubmitted kits is for local agencies to conduct audits.

2. Little is known about the age of unsubmitted kits.

Today, DNA testing is common, but 10 years ago it was not. Experts hypothesize that a large proportion of unsubmitted kits may be from older cases. Knowing how old unsubmitted kits are is important because older cases are processed and investigated differently than more recent cases. In older cases, evidence may be degraded, cases may have been adjudicated, victims may need to be notified in different ways, and suspects may be more difficult to locate.

3. Submitting a kit to a crime lab does not mean the lab will obtain usable DNA.

Not all kits contain biological evidence. Not all biological evidence yields usable DNA. Sometimes evidence is so severely degraded the lab cannot obtain a DNA profile.

4. Even if the police have a suspect, testing a kit can be useful for a number of reasons.

In the majority of sexual assault cases, the victim knows the perpetrator, which may be one reason police might not send a kit to the lab — they do not need to confirm the identity of the suspect. But DNA collected in cases with known suspects and entered into the national DNA database could link suspects to other crimes, including other sexual assaults.

5. The cost to test a sexual assault kit varies widely.

Several factors affect the cost, including the nature and complexity of the evidence and the prices labs have negotiated with vendors. Costs also vary for validating DNA profiles, uploading profiles into the national database, and conducting the necessary follow-up case work, including investigation and prosecution.

With continued scientific investment, NIJ believes testing will become faster and cost less and that systems can be put into place to improve the way evidence is tracked. Scientific investments will also help professionals identify practices that lead to the best ways for investigating and prosecuting sexual assault cases.


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Date Created: April 27, 2015