He had a family. A job. A role in his church. And for decades, no one suspected he could be the BTK killer.The story of The Hunt for the BTK Killer, is disturbing enough. But the psychology behind it is even more unsettling.Famed forensic psychologist Dr. Katherine Ramsland shares what she learned through her personal relationship with Dennis Rader: from the childhood patterns that shaped him, to the way he switched between personalities, to how he was able to live with what he’d done.