Motivation for murder

Did you know that while there are limitless motives for people to murder other people, they all boil down to a handful? When I recently researched homicide methods and motives—I’m sure that whatever watch list I wasn’t on before, I’ve now been added—I found some interesting statistics.

When the Australian Institute of Criminology compiled data on motives for murder about 20 years ago, they found three primary reasons for murder: revenge, drugs/money, arguments.

In fact, if you’re an Australian man, your chances of dying because of an argument of some kind are greater than 50%, and if you’re an Australian woman, they’re closer to 60%. Here are the raw statistics:

The more recent statistics (2020-2021) paint a similar picture, but unfortunately the AIC no longer does helpful tables like the one above, so here are the murder motive statistics in written form:

  • 34% were dispute-related, with 28% following an argument (n=59) and 6% relating to a dispute about money or drugs (n=12)
  • 4% (n=8) were by perpetrators experiencing a psychotic episode or other mental health crisis at the time of the homicide (a new criterion)
  • 5% were motivated by revenge (n=2), jealousy (n=5) or separation from an intimate partner (n=4)
  • The motivation or circumstance was not apparent for a quarter of homicides in 2020–21 (25%, n=53) and was not known for 18% (n=38) of incidents.

The FBI doesn’t report homicide data quite the same, but the data available shows a similar motive pattern:

  • 43% were dispute-related (n=6,030)
  • 16% were related to another crime (n=2153) including 4% specifically to drugs (n=591)
  • A much greater volume (41%) were unknown (n=5197) compared with Australia
  • There is no classification for revenge specifically.

(For those who wish to read the raw data, the links to the original documents are here (Australia 2003), here (Australia 2020) and here (US 2019).)

What does all this mean for the suspense author? When we write motivations for crimes, disputes or arguments (of all kinds) are sadly the most realistic. Revenge is not quite as common in real life as in fiction. And opportunistic homicides to cover up or in the commission of another crime are depressingly common.

To round this out, I’ll leave you with an insight from an interview with Alfred Hitchcock by Andy Warhol where they discuss the motivations for murder. According to Hitchcock, “They do it in desperation… [and] a lot of it’s done on the spur of the moment”. Which suggests that whether they occurred fifty, twenty or three years ago, the motivation for humans murdering other humans remains the same.