After a decade in which DNA evidence has freed over 100 people nationwide, it's become clear that DNA evidence isn't just proving wrongdoing by criminals, it's proving wrongdoing by police and prosecutors. In this show, we look at what DNA has revealed to us: how police get innocent people to confess to crimes they didn't commit and how they get witnesses to pin crimes on innocent people.

<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" /> Ira Glass: ‘So in the end, Michael Crowe, 14 years old, confesses to the murder of his own sister and even sort of believes that he did it. And one of the most disturbing things about watching this it is the police officers who do this, they don't seem like they're corrupt cops. Do you know? They don't seem like the guys who are out to pin a murder on an innocent kid. They seem like they actually believe they're doing their jobs and doing a good job of it and they believe he did it.’

 Richard Leo: ‘I think that's absolutely right. There's no indication from watching that interrogation that they are corrupt. In fact, if they had been corrupt, they probably wouldn't have tape recorded it. And I think they genuinely believe that he's an evil person who did this. But the police, in this case, are just sloppy and they're stupid. It's not that they're corrupt or evil. They should have investigated more before they started interrogating anybody. That's one of the fundamental precepts of all police interrogation training. You never start interrogating until you've completed your investigation.’

Ira Glass: ‘I have to say, I can't figure out which I find more disturbing, the thought that some police are corrupt and forcing confessions out of people or this thought that basically, this is just the institutional way that we get a confession in our country. Do you know what I mean? "This the way we do it. We lie to them about the evidence we've got." You know what I mean? That seems, in a way, more disturbing. Or I can't even tell which is more disturbing.’

Richard Leo: ‘When I teach this subject to undergraduates, they're often split about that as well. I think myself, personally, I am more distressed by the idea of corrupt cops because I think many corrupt cops, whatever area of police work it is, have crossed a moral line and there's really a point of no return and they just get dirtier and dirtier and dirtier.’