A&E’s newest original documentary, BTK: Confession of a Serial KillerThe American serial killer, Jan. 8, is the story told in “The Bone-chilling Story of American Serial Killers”, premiering January 8. Dennis RaderHe was known as BTK (bind, torture and kill), his nickname.

CelebHomes Exclusive Clip: Dr. Katherine Ramsland—who wrote the 2016 book Dennis Rader, BTK killer and serial murderer confesses to his crime— shares her puzzling correspondence with the murderer. They have kept in touch over a decade, as Rader is serving 10 life sentences at El Dorado Correctional Facility, Kansas. “My initial communications with Dennis Rader were kind of interesting,” Ramsland, who holds multiple degrees, including in forensic psychology, explains. He liked that I brought credentials, because that meant he was taken seriously.

“But, at the exact same time, I was being tested by him.” Continue she says. She continues, “He told me he wanted my to solve some code and he loved working with codes. I began receiving cut-out pages of magazines and newspapers from him. He would circle certain things, and make strange comments.