Dennis Rader (pictured left in 2019), the unsuspecting church leader and family man later identified as Wichita's prolific BTK killer, simultaneously thinks of himself as a 'monster' and a 'good person who did some bad things,' according to a forensic psychologist who corresponded with him in code for nearly a decade. In 2005, then 60-year-old Dennis Rader - who gave himself the moniker 'BTK,' which stood for 'bind, torture, kill' - pleaded guilty to killing ten people between 1974 to 1991 to sate his sexual sadism. Forensic psychologist Dr. Katherine Ramsland corresponded with the locked-up killer for over a decade in coded letters to better understand what drove the outwardly-ordinary man to kill. Now, Ramsland is sharing her insights about the killer in a new A&E docuseries, 'BTK: Confession of a Serial Killer,' which aired on January 8. Rader is pictured right dressed as one of his victims in a chilling photo uncovered by police after his 2005 arrest.