Why do people kill?
That’s a question a lot of thriller and mystery writers ask themselves when they’re plotting a new story.
I apologize that this is more grim than my usual posts, but writers, we sometimes deal with things like this! This post is kind of a mini murder motive generator for writers, and if you like it, you’ll also want to check out my 25 Mystery Clues for Writers.
Let’s get into it!
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!
I hope this list was helpful for you! I have more motives for murder in my book Master Lists for Writers. Check it out, if you haven’t already!
Writers, any other answers to the question, Why do people kill?
If you have other ideas, or general thoughts about writing a great murder mystery plot or subplot, let me know in the comments! Thanks so much for reading, and happy writing!
fantastic list
(PS. I think gender identity is the preferred term over sexual orientation.)
denise
Oh you know what, I’m no expert, but we might be talking about two different things there. Sexual orientation = who you are sexually attracted to (gay, straight, bi, etc.), and gender identity = what gender you identify as. But gender identity can be a reason for prejudice and hate, too, so I could’ve added it to the list!
Another wonderful and insightful blog. I am writing a Romantic Suspense story.
Alex became a bodyguard to a mobster when he saved his life. The man offered him a job as a bodyguard because he needed the money he accepted, thinking it would be for a short period. The mobster was killed one evening. Alex killed the killer of his friend(the mobster.) He saw this as an opportunity to get out of the mob. He killed to protect someone.
Zenia killed two people. Her husband was a mobster. One night, he went down to the kitchen to warm a bottle and feed it to their baby. Someone broke in and when they shot him in the back, they killed the baby too. Grief stricken and in rage, she killed two people who were with the true murderer.
Theme: Sometimes good people do awful things.
Thanks for the kind words, Carol! It sounds like you are really thinking through motives in your story. I hope the writing is going well! Thanks for commenting!
Someone murders someone who they know will continue harming innocent people if not stopped and the justice system has failed to stop them.
Bill, this is such a good one! Thanks for suggesting it!
Good morning Bryn
May I add a motive ?
The killer has murdered someone who was the witness of a financial fraud
Thank you for your blog I like to read it !
Hi, Philippe! Oh, that’s a really good suggestion for a motive. Thank you! And thanks for reading, and the kind words. 🙂 Have a great weekend!
Then there’s the psychopath/sociopath – no motive required 🙂
That’s true!
This one kind of goes along with #10:The murderer is taking revenge for a loved one who was wronged…
Someone was blamed for a murder and being attacked my the victims loved ones, the person in love with the accused murders all the people who attacked the accused person. But then what if they confess their undying love for that person and they don’t reciprocate those feelings so they kill them too?
This is an intriguing topic, yet I am amazed while reading this. Honestly, I do not know how to express my thoughts, but all I know is all people are born good people, and if we choose to love rather than hate, maybe crime will be lessened.
Whatever the motives is, killing someone is not a solution.