There was a story on
This American Life (act two) last year about how the police convinced a 14 year old kid that he murdered his own sister. DNA evidence later proved that he didn't do it, but they kept him in the interrogation room for so long that he'd believe anything they said. They actually convinced him he did something that he didn't do, and he confessed to the crime.
I think there was also a Dateline or 60 Minutes show on police interrogation techniques being akin to brainwashing a while back. Not sure how it'd work against adults, as Mike Hawash was, though. But it seems to have happened many times in the past, where evidence has later proved that the confessors didn't actually do it.