"The DNA testing and evidence only occurs in a situation where the assailant leaves biological evidence behind. For the most part, we are talking about rape cases where there is semen left that can be tested. There are occasionally non-rape cases where the assailant may have left behind hair fragments or fingernail fragments that are of a sufficient quantity that they can be tested for DNA. But if no biological evidence is left behind, which is what occurs in most cases in the criminal justice system, no DNA testing can occur. The second qualifier is: even among those cases where there is biological evidence left behind that can be tested, if it is not gathered and collected and preserved properly, you will end up with a false test.

So I think the possibilities with DNA testing are immense in terms of being able to exonerate certain people, or on the other hand, definitively indicate that they were the perpetrator. But it still will not be available in somewhere between 70 and 75 percent of the cases in the criminal justice system, perhaps even more. So it is not the silver bullet that is going to solve our criminal justice system problems."