For almost 30 years, the city of Wichita, Kansas was terrorized by a serial killer. He called himself BTK , a nickname patterned after the phrase “bind, torture, kill” — the signature way he would leave bodies for police to find. His victims varied, first a young family, then women of varying ages and economic backgrounds — sometimes going years between murders. Investigators were assigned and reassigned to the case, poring over clues and evidence. These included letters from BTK himself,