We usually think of demons as pursuing loftier goals, such as wayward souls, not penises. But for the lust murderer, sexuality, power, and domination are intertwined so tightly they bleed into one another. It is difficult to tell where sexual lust leaves off, and lust for blood takes over. In contrast, the sadistic murderer kills as part of a ritualized sadistic fantasy. Because psychopaths have a low arousal rate, it takes more to stimulate them.
Macabre mutilations excite the lust murderer.
For them, killing triggers a bizarre sexual fantasy which had developed in the dark recesses of their warped minds. Masturbation generally occurs after death, when his fantasy is strongest. Because the fantasies do not involve an actual person but a symbolic, sacrificial victim, the violence can escalate after death. Many of the serial killers we have discussed admit to an abnormally strong sex drive. Yet he fantasized about dead women, not living ones.