This is a very interesting question.
I think that there are many both conscious and unconscious factors that determine destructive behavior. The conflict between the id and super-ego (mediated by ego) can, at some level, be understood as a conflict between needs and social norms. Murder seems to be universally accepted as "bad behavior" so it must be coded both on the conscious and unconscious level in our psyche, therefore, I assume the wide majority of people try to combat destructive impulses with defense mechanisms.
Here is a set of questions you can toy with:
- When would your evolutionary ancestor murder someone?
- When is it okay to murder someone? Why?
- What behavioral and mental changes you'd have to undergo to become
the evilest person you know of?
Jordan Peterson does quite a good job describing what leads to resentfulness and how can it manifest itself in the world in his biblical series. / Short clip about him discussing hell.
Jungian concept - Shadow - is also an attempt to articulate evil aspects of a human being which is worth exploring. Especially because Jung stressed the importance of getting to known your own shadow. In other words, incorporating the evilest aspects of your personality and learning how to live with it properly.
One of the things that are common among rape victims and soldiers who develop PTSD is the naivety and inexperience prior to the accident of evil. Peterson and other psychologists hypothesized that PTSD can be a shock effect upon realization of the depth of the evil within self or within another human being.
Based on this, I'd say that almost all people have thought about murdering someone at least once, however, have stopped / didn't behave destructively. I'd go further and say that the wide majority of people at a certain point of their lives have fantasized about murdering someone and enjoyed that fantasy.
Based on my personal experience and practice, I'd say murder impulses, desires and fantasies are a very good self-improvement tool that one can use to understand the deep nature of their own personality. Murder correlates with some aspects of our personality. Assumption #1: those personality traits (for example narcissistic features) have to do with the evolutionary survival patterns that can, in some sense, be useful. However, there must be a trigger behind extremes - assumption #2: those triggers are subtle and very hard to notice. So, if one can trace the link between feature and trigger they can improve their lives.