In the 1970s John E. Douglas was a relatively young FBI agent who would travel around the US teaching police officers the bureau's tactics. John knew he was inexperienced compared to the seasoned detectives he was instructing. But he had an idea to accelerate his learning: go into prisons and speak to notorious serial killers. They weren't called 'serial killers' back then. John helped come up with the term. Through the interviews John was able to understand how the minds of these criminals worked and how it could be applied to solve open cases. But the gruelling work took its toll on John. Andrea Kennedy spoke to him about how it began to erode his mental health and very nearly cost him his life.

Image: murderer Edmund Kemper (left) with former FBI agent John E. Douglas (right)

Credit: supplied by John E. Douglas