A recent investigation has revealed that tens of thousands of rape kits (or more) were never tested by police in the US. Victims of sexual assault who are tested for DNA evidence must go through an invasive process that can last four to six hours. When analyzed, the tests can help identify offenders and prevent future assaults as well as wrongful accusations.

The investigation lead by USA TODAY found that some police departments were sending as little as two in 10 kits to crime labs. The fact that each kit costs roughly $1,000 to analyze could part of the problem. And in most states, there are no written guidelines for how to process sex-crime evidence. As a result, the fate of the evidence is often in the hands of the individual officer involved.

It's impossible to estimate how many sexual assaults by repeat offenders could have been prevented if these untested kits were analyzed. The investigation is not over, and the number of untested kits are expected to reach the hundreds of thousands.

Cover image: PolitiFact