Why Do People Become Serial Killers.?

Because certain people are compelled to kill. They combine the elements of sex and violence early-on in their dreams as pre-adolescents and after they are done with torturing and killing small animals, which is what MOST do, they want (or need, depending on which way you look at it) to move onto something bigger, humans. The conventional standpoint holds that they CAN kill for not one reason but three. It's said that the vast majority have been physically abused by one, or both parents, have had (or have) a mental illness, and  have suffered an injury to the pre-frontal lobe (the part of the brain responsible for emotions, cognition, error detection, volition, a sense of self. Also, 60% wet their beds after the age of 12, this can be very humiliating to them as they feel already feel immature, and inadequate on the inside, sensing that they are different than others, but not knowing why. (Most if not all of the information above should prove to be true, if it is not then tell me.)  Oh and why are you interested, I'd like to know.