But emotion is something Rader himself hadn't shown until now, reports 48 Hours Correspondent Erin Moriarty.
In Wichita, she
Moriarty spoke with Rader, 60, several times.
Prosecutors call him the "gentleman serial killer."
He's so ordinary and docile, Moriarty says, that you have to constantly remind yourself that he's also a cruel killer.
But he left no question of that during a plea hearing in June, as he calmly reeled off details of the crimes he committed.
Said Rader, at the time, of one victim: "I took her to the basement and eventually hung her. … I had some sexual fantasies, but that was after she was hung."
Hidden behind the face of the guy next door, notes Moriarty, is the heart of a cold-blooded murderer who took the lives of 10 people in Wichita.
"I manually strangled her (until she died) when she started to scream," Rader told Judge Gregory Waller about his first victims, four members of the Otero family, in 1974.
"First of all," Rader said, "Mr. Otero was strangled. … After that, I did Mrs. Otero. I had never strangled anyone before, so I really didn't know how much pressure you have to put on a person, or how long it would take."
Until he was caught earlier this year, Rader had sent letters to the police and press, calling himself "BTK," for bind, torture, and kill.
He hid from police right out in the open, working most recently as a dogcatcher.
In his office, he kept neat files on each of his victims, referred to by Rader as "projects."