On May 7, 1984, on a blustery day in Seattle, Gary Ridgway sat in an interrogation room. Strapped around his arm was a lie detector. After answering a series of questions, the investigators told him he was free to go. Gary would soon come to be known as one of the most prolific serial killers in United States history. But that day, he had beaten a lie detector test and walked out of the police station a free man. 

When the lie detector first found its way into police stations it was touted to the press as 100% accurate. But soon the cracks begin to show. Those claiming innocence would fail the tests. And even as The Green River Killer proved he could best the machine its popularity continued to grow. 

American Innovations: Lie Detector explores the evolution and validity of the Lie Detector. Listen at wondery.fm/liedetector