The most of you could say no, but you would be lying to me. The brain has the complete potential to create all kind of thoughts, it can be promoter of good things as much as bad things, the creativity is the preferred tool of the mind to achieve its goals. Think and dream with horrible things has nothing to do with an evil person, at least in most of cases. Because of one crucial factor, the controller of every action we do, the conscience. I confess that I have sometimes scenes created by my imagination in which I stab someone, or I shot someone. In some cases, my imagination turns darker, but that´s the moment when my conscience interrupt, it says something like: "wow, what am I thinking? I´m crazy? No way that could happen". I ensure myself through the conscience that I´m just being victim of the small dark side that has my mind, and everybody´s mind has. You should know that curiosity has bad ways of applying depending on the theme what it´s involving the second world war is proof of that. The human has the same abilities to destroy and to create.
The break point is in how was manipulated the consciousness in every person, how this person has been raised. The correct thing to do is so subjective, the hero of one nation can be the terrorist of another, is matter of perception. The true thing is that we will never know how the world really is, we will know how world is under our perception. Perception that is strongly related to culture and personal habits, that´s why the childhood is the most important stage of life, it´s the stage where you define what kind of person you will be, it´s like an action in chain, bad childhood equal to bad habits equal to bad person.
Take a time to study the childhood of the most famous serial killers, rapists, kidnappers, scammers, gangster, etc. You will find notices like: "Killing birds with a stone and shredding them was his favorite play", "His uncle obligated him to have sex with him" "He was abducted and mistreated by the kidnappers" "His father show him how to deceive people since he was a kid".
The childhood has deeply consequences in the performance of that person when it grows. In that stage of his/her life, he/she will form the consciousness, crucial factor to make the right choices and don´t end up in jail, because the world is subjective, but the rules are clear, if there was no control about the behavior of human beings the disaster wouldn´t have an end. The social structure imposed in this modern age has its fails, but also has its successes.
However, I said that a bad childhood is equal to a bad person, but like everything in social matter, it haves exceptions. I would like to frame the cases of people that get into a bad life full of crime, and then, one day they take the choice to rehabilitate. Do legal things, have stability, have a wife, a child, a family. It´s not common, but it happens. Those rehabilitated criminals, in most of cases explain that they have to took the neutralization technics to do those immoral things, but, what are the neutralization technics? They establish the sort of justifications that criminal believes to mitigate their guilt after commit a crime. This technics are only applyable when the subject involved at least has a little consideration about what is good and what isn´t, when they have a little bit of consciousness. However, the worst criminals are not worried about evil and good, they have no consciousness, their childhood and adolescence was the horrible enough to make them indifferent, to make them sociopaths and/or psychopaths. The worst kind of criminal indeed, because their absence of guilt, making them capable of everything that its corrupted brain could think of.