No. They dont. I have read all 3 of John Douglas' books on Sexual Homicide and serial killers and one thing is certain: At some point in their fantasy development, a serial killer experiences what Douglas calls a triggering event and he kills to try and fulfill his fantasy. From that point on there is no turning back, no choosing to be good from then on.The compulsion to kill controls them for the rest of their lives. Douglas goes on to say that the only thing you can do at that point, and remember that he interviewed scores of these maniacs, is kill them.