its both nature and nurture.
most serial killers had VERY cold, distant and abusive mothers. its one of the major traits of serial killers. they have NO desire to save a ho, instead they want to kill a ho.
That's the nurture part... or non-nurture, as the case may be. The
nature part is that extremely violent people have been show to have brain-wave abnormalities that are more-or-less consistent in that a certain portion of the brain is severely understimulated. Perhaps it takes something as extreme as murder to sufficiently stimulate that portion of the brain. Interesting thing is that it has also been shown that such people can be completely rehabilitated by playing a sort of video game that develops that portion of the brain.
