Murder Premeditated Killing With Malice Aforethought

1. A physical fight turns deadly

When we’re asking, Why do people kill—or what makes a human being cross that line—it’s important for mystery writers to remember that sometimes it’s accidental. A murderer may inflict more damage than they intended. On the other hand, it’s also possible that in a fight, the murderer becomes enraged and decides to kill the other person instead of just hurting them.

2. Someone murders their spouse, partner, or ex out of jealousy

In the U.S., men murder about seven times more often than women do. The majority of female murder victims are murdered by a husband, boyfriend, or a male ex, and jealousy is one of the main motives in these cases. Risk factors here include a male partner who is abusive, who uses alcohol, and who owns a gun. Of course, women may murder out of jealousy, too.

3. The murderer hates the victim’s politics, religion, or sexual orientation

In a case like this, the murderer may feel like a crusader.

4. Someone murders an abusive partner or family member because they’re sick of the abuse

The abuse may be physical or emotional.

5. The murderer kills the victim in order to steal from them

This may be premeditated murder, or it may just happen in the course of a robbery.

6. The murderer wants to collect life insurance money or an inheritance from the victim

This is a really popular reason that a character becomes a murder suspect in a murder mystery novel.

7. A spouse wants out of a marriage, but doesn’t want to pay alimony or have others think badly of them

In this case, the murderer views murder as a means of “instant divorce.”

8. The killer wants to eliminate a rival

This could be a rival in love, politics, or some other type of competition.

9. The killer is taking revenge for being wronged in their career

The victim may be a boss who fired them or a business partner who cheated them.

10. The murderer is taking revenge for a loved one who was wronged

For example, this could be a father killing his daughter’s rapist, a son killing the man who ruined his father financially, or a mother killing the bully who drove her son to suicide. Of all the answers to the question Why do people kill, this is probably the easiest one to understand.

11. Someone takes revenge on a person for rejecting their romantic overtures

While the murderer in this case has not been wronged, they may still perceive themselves as being wronged or humiliated.

12. Some mistakes the victim for their actual intended victim

After I wrote this, I remembered that I have firsthand experience with it! I lived in a duplex and there were gunshots one night. It turned out that my neighbor had a friend staying with her, and the friend’s ex-boyfriend came by with a gun. When my neighbor came to the door, he shot at her from his car, believing her to be his ex-girlfriend. He just missed—the bullet hit the doorframe. I’d been outside just minutes before, taking my trash out to the curb.

13. Someone murders a family member that they perceive as needing an extraordinary amount of caretaking

This is a very sad situation, and it does happen.

14. Someone murders their pregnant partner due to extra stress and/or fear of responsibility

In the U.S., people who are pregnant are much more likely to be murdered by their partner than to die of any other pregnancy-related cause. One option here is that the murderer is a married man whose mistress has gotten pregnant.

15. The victim was a witness to a crime

This is definitely one to consider if you’re writing a thriller or mystery!