Motives For Murder When Plotting A Mystery


by C. 51hWuZ3U3VL__AA160_F. Carter


When I started plotting my first mystery novel, Death Of A Dummy, the first thing I needed was a believable motive for murder.


As an all-around nice guy, I found it difficult to imagine any motive being powerful enough to justify homicide. To my thinking, it would have to be a life-and-death act of self-defence, or revenge for the death of a close family member. If money was the motive, there would need to be a big pile of it, indeed. Certainly nobody in their right mind would bump somebody off for a measly $10,000 life insurance policy, or because they were too lazy to file for divorce–right? Well, the sad truth is that people do commit murder for a surprisingly high number of stupid and trivial reasons.


I know what some of you are thinking: what does this blowhard know about murder? No, I don’t have a PhD in criminology and I have never worked in law enforcement. My expertise comes primarily from my own endless, secret wellspring of knowledge: reality television! I’ve watched hundreds of episodes of Forensic Files and Motives & Murders, and I took copious notes just for you. I’ve also read thousands of stories in Alfred Hitchcock, Ellery Queen, and Mystery Weekly Magazine. And anyway, I make no claim that this list is accurate or complete. I just want to help aspiring mystery writers in any small way I can.


Since I’m most interested in cozy mysteries, I’ll be including specific examples for an imaginary cozy series set around a perfume shop. So here is some backstory. Let’s say that our protagonist, Maria, was a renowned scent designer from Milan, who gave up her lucrative career to marry a single dad she met while attending a perfumers conference in Canada. Her new husband (a taxi driver) was killed during a robbery, leaving Maria to raise his teenage daughter by herself in a small town. Using the generous severance package she received from her last job, she opens a boutique perfume shop and names it “Smell You Later.”


Unlike the subtle fragrances she brews up in her backroom beakers, Maria has a strong presence. She’s sharp-tongued and tough and knows how to deal with fools–like the young suitor who’s been sniffing around her daughter, or the local Barney who is more interested in Krispy Kremes than in finding a killer…



Alright, let’s get to the murder motives!





  1. Kills to cash in on a life insurance policy
  2. Kills to increase his shares or interest in a business or property
  3. Kills other beneficiaries of an inheritance, insurance payout, or lottery windfall
  4. Kills someone who is suing him
  5. Kills someone who is stealing from him or making a hostile takeover of his company
  6. Kills someone who for legal reasons will obtain his money or property
  7. Kills for a winning lottery ticket, treasure map, claim, bearer bonds
  8. Kills to increase drug or business territory (expansion of wealth)


Example: Maria made her commercial landlord a partner in her perfume shop in exchange for free rent. When he winds up dead, the police suspect Maria because she would benefit from his death thanks to a legal clause. So Maria must do her own investigating to clear her name. It turns out that he was actually murdered for his life insurance by his spoiled nephew, who saw an opportunity to frame Maria for the murder. [2 motives used]


Freedom  From prison, abuser, kidnapper


  1. Kills controlling husband or boyfriend who won’t let her go
  2. Kills blackmailer who is threatening to reveal his true identity or details of a crime he committed
  3. Kills a witness to his crime to avoid going to prison
  4. Kills to avoid being deported to his home country


Example 1: Maria’s new shop assistant is a young man who has a good nose for perfume, but learns the hard way that nosiness isn’t always a good thing. In fact, it gets him killed when he confronts a robber that he witnessed fleeing from the bank across the street.


Example 2: A regular customer of the perfume shop is a mild mannered, skittish woman that wants to smell good and feel attractive again. When her husband winds up dead, everyone suspects she did it to escape his abuse [motive 1]. Her husband is one of the contractors who worked on her shop.  In actuality, he was murdered by an electrician who he was blackmailing for being an illegal immigrant [motive 2]. They worked together on the renovations for Maria’s perfume shop.





  1. Kills to remove competing suitor(s)
  2. Kills to exact revenge on spouse or paramour for committing adultery
  3. Kills business partner or partner in crime for double-crossing him.
  4. Kills to get revenge on a snitch
  5. Kills before spouse can take his children away
  6. Kills due to a secret obsession
  7. Kills as mercy killing (terminally ill family member)


Example: A lady from a neighboring business brings Maria a scarf with perfume on it. She claims it was left behind by a customer and that she wanted to know what the amazing scent was. Maria says it was a custom creation for a customer. In reality, the lady found the scarf in her own home, and wanted to find out who her husband was having an affair with. After she discovered the paramour’s name, she murdered her by strangling her with it.





  1. Kills co-worker or boss to get a promotion
  2. Kills a witness to something that would result in demotion
  3. Kills spouse who is about to file for divorce, to avoid embarrassment. Typically involves well-respected community leader.
  4. Kills blackmailer who would embarrass him by revealing a secret (affair, criminal record, unsavoury affiliations)
  5. Kills a competitor who always beats him in a prestigious contest
  6. Kills for power or prestige in gang


Example: It’s election time and Maria’s friend, the town mayor, is arrested for murdering his wife. His wife was flagrantly cheating on him with another woman, and he was being ridiculed in the media by his opposition [motive 1]. In actuality, it was his competitor who was framing him for murder so that he could win the election [motive 2].


Other Motives


  1. Kills someone who bullies/attacks him for extended time
  2. Kills abusive husband/boyfriend, or abuser of family member
  3. Kills someone who looks like him, to avoid a determined hit man.
  4. Kills someone ahead of him or family member on organ transplant list
  5. Kills while intoxicated
  6. Kills someone who looks like him, to fake his own death and claim his own insurance or inheritance (requires conspiracy usually with spouse)
  7. Kills innocent party to hide the real murder target or make the murder look like a random act
  8. Kills as activist to protect animals, unborn babies, etc.
  9. Kills acting as a vigilante



That’s it! Please note that I’ve left out many motives that I felt wouldn’t be appropriate for a cozy mystery (i.e., hate crimes, insanity). Also, keep in mind that most of these could be extended to the killer’s friends and family. In other words, whatever the killer does for himself he could also do in the name of a family member.


If you find this information useful, please share it on your Facebook page or link to it on your own website. It costs you nothing and would mean a lot! Next month, I plan to continue with my Perfume Shop example and discuss the methods of murder.


Until then, happy writing! And happy new year!


2 thoughts on “Motives For Murder When Plotting A Mystery

Add yours

  1. Hi Julie– I’m an old granny and cozy mystery writer too! I write, among other things, The Two Old Biddies Series, and the Senior Delinquents Series. I like that your motives are a bit more cozy and less involving the crazy things we sometimes see in the news. 🙂


Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Blog at

Up ↑

%d bloggers like this: