I think there are 3 basics reasons for killing a person.Maybe we could look at it?
Dissect the nature of killing itself?
Outside of partisan, sociological, psychological known frameworks?
The nature of the desire to kill itself?
The actual impulse to kill?
What makes killing an option?
ETC
1. A person values themselves and their life. Self-defense. This reason is in the eye of the beholder whether it is justified or not. This person values their life and the lives of family or friends who they feel are being threatened.
2. A person does NOT value their own life in any way and feels entitled to take a life to make up for how life has cheated them. This is a person willing to risk their own life, spending life in prison, or being killed themselves. This is the person killing for a pair of sneakers, committing mass killing, or enraged because their partner has left.
3. A person DOES value their own life. Very much. But darn, why do I have to split assets during a divorce? These are the sociopaths of the world. It's usually about money and win-ning at any cost. These people just aren't wired right. They can't be fixed. It's easier to murder than to get a divorce.
Serial killers are a different story. I think the 3 motivations above are pretty basic but most killing fits generally into these categories. Just MOO thinking on the fly.