It was a case that had confounded investigators for three decades, suddenly "solved." But when the police arrested Pedro Hernandez in 2012 and interrogated him about the disappearance of 6-year-old Etan Patz in 1979, they didn't record the proceedings until he formally confessed -- nearly seven hours later. ProPublica’s Joaquin Sapien joined Steve Engelberg to talk about the dubious case against Hernandez in the Patz case and the phenomenon of false confessions.

The most pressing question, of course: Why would someone falsely confess to such a horrible crime? Police are trained to use psychological tactics in interrogations, Sapien said, making certain people more likely to confess to crimes they didn't commit. At particular risk, he said, are people who are mentally ill, have low IQ, and are under suspicion in a crime that has been widely covered -- increasing their knowledge of the case.

"In states that have the law, where it's required that you videotape, law enforcement really likes that it's the law, because it makes it very simple for them in court. They can just go to the judge or jury and say, 'This guy is now claiming that his confession is false, but look at the tape.' "

You can hear this podcast on iTunes and Stitcher. For more on this investigation, read Sapien's investigation: Missing: A Boy and The Evidence Against His Accused Killer.