After 1978, while BTK seemed to disappear from Wichita, he was actually quietly stalking victims and killing with more sadistic violence than ever before.

On the surface Dennis Rader seemed like a regular guy, but what lied beneath was a sinister fantasy life he enacted under the guise of his alter ego, BTK, while terrorising Wichita, Kansas.

The murderous crime spree of BTK continues as there were seemingly no signs from his upbringing that would indicate he would become a serial killer.

Dr Katherine Ramsland gets first-hand insight into the mind of the BTK Killer, Dennis Rader, and the fatal mistake that led to his capture.