Forty-six states that have passed laws to enable inmates to get DNA tests on their cases. In many places, says the New York Times, prosecutors are using new arguments to get around the intent of those laws, particularly in cases with multiple defendants, when it is not clear how many DNA profiles will be found in a sample. The laws were enacted after DNA evidence exonerated a wave of prisoners in the early 1990s, when law enforcers strongly resisted reopening old cases. Continued resistance by prosecutors is causing years of delay and, in some cases, eliminating the chance to try other suspects because the statute of limitations has passed by the time the test is granted.
A recent analysis of 225 DNA exonerations by law Prof. Brandon Garrett of the University of Virginia found that prosecutors opposed DNA testing in almost one out of five cases. In many of the others, they initially opposed testing but ultimately agreed to it. In 98 of those 225 cases, the DNA test identified the real culprit.