Why a Confession Isn't Proof

From the outside, it may seem that you'd confess to something serious only under torture. In reality, a long interrogation, exhaustion, and confident pressure can be enough. A person can end up feeling that confessing is the only way to stop what's happening right now.

The logic of someone confessing is usually this: I'll say anything to make this stop, and then they'll sort it out and the truth will come out. They rarely do: after a confession, investigators consider the case closed and stop checking other possibilities.

The last point explains the most frightening feature of false confessions: they can be detailed. Details that “only the perpetrator could have known” often enter the story through the investigator's questions, photographs on the table, or the press.

The main safeguard is simple: record the entire interrogation, not just the final confession. A full recording makes it possible to see where the details came from and exactly what was said to the person before they agreed.

The second is to check the confession against independent evidence. A confession is considered strong if it contains something that can be confirmed and that wasn't mentioned during the interrogation: the location of a hidden object, or a detail unknown to investigators. Everything else requires separate evidence.