the locked room mystery

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By Kevin G. Chapman

What’s the next great locked room mystery?

First, let's investigate what one is ...

"locked room mystery" definition

While browsing new mysteries, you see this description:

Grandfather is found dead in the little Grecian lodge among the rose gardens of his estate. The Inspector believes that the evildoer is among the genteel family gathered at the rural manor.

The night he died, cantankerous Sir Richard was arranging to disinherit his offspring. Someone took murderous steps to protect their own interests.

But the murderer left no scuff in the carefully raked sand paths and no trace on the manicured lawns.

Your first reaction would probably be: “That’s been done so many times!”

And you’d be right. This is a description of one of the classic variations on the “locked-room murder mystery.”

A family is gathered together. Everyone has a motive to kill the old man. He dies suddenly under circumstances that appear to be impossible. All the family members are suspects, but who done it?

(If you saw the 2019 film Knives Out, you saw an exceedingly well-crafted example.)

If the blurb above were written today, it would be doomed unless the story had some very unique twist or amazingly crafted characters and subplots. In this case, the description is from the 1946 novel, Suddenly at His Residence, by Christianna Brand. So, at the time, it wasn’t such an old cliche.

some locked room mystery solutions

Even in 1946, however, the trope was not original.

In 1935, John Dickson Carr in his classic, The Hollow Man, had his protagonist, Dr. Fell, give a lecture in which he expounded upon the seven types of locked-room mysteries:

  1. the victim actually killed himself;
  2. the death was actually accidental, so there was no murderer who needed to escape from the unescapable space;
  3. the lethal weapon was poison (gas or otherwise) so that the murderer was not really there;
  4. the death was caused by a booby-trap so (again) the murder was not really there;
  5. the murderer impersonated the victim;
  6. the kill is accomplished from outside the room using a disappearing murder weapon (an ice-knife or ice bullet), disguising the possibility of an extra-territorial cause; and
  7. the victim wasn’t really dead until the killer entered the room along with the police or other witnesses, at which time the killer executes the murder, making it seem like it happened earlier.

modern locked room mystery books

The mystery-writing community has been trying to come up with new variations for the locked room mystery trope for nearly a hundred years.

There are anthologies of them, including Locked Room Murders and Other Impossible Crimes: A Comprehensive Bibliography, by Robert Adey (1992). Mr. Adey identified thirteen more “standard” tropes that had evolved over the intervening years.

Does that mean they’ve all been done?

Without reading them all, including the thousands (hundreds of thousands?) written and self-published in the past decade by indie authors, it’s impossible to know.

There are certainly many that have been done to death (sorry!). Certainly, those should be retired from future use (feel free to comment on which are your least favorites).

The question is: what are the great ideas that have not been written yet?

Here are a few crazy ideas:

  1. Using a remote-controlled knife-launcher hidden in a secret compartment behind a wall (that will never be found after the murder because nobody is looking for it), the killer triggers the spring-loaded knife with his smart phone, with which he/she also watches the room through the drone-mounted camera hovering outside the window (leaving no footprints in the snow).
  2. A surgeon implants a microchip that triggers a heart attack based a signal sent through the victim’s home Wi-Fi.
  3. During a fishing trip, the killer poisons the victim’s hook with a chemical that kills him as soon as it interacts with his otherwise benign nightly medication.
  4. A master virologist creates a highly contagious bug, infects his unsuspecting mule, then sends him onto a cruise ship for the purpose of infecting the immuno-compromised intended victim, accomplishing the intended assassination, but also spreading a global pandemic. (OK, we definitely don’t need this one.)

Have any of these been done already? Comment and let me know.

Can you come up with a variation that can’t be forced into one of the existing 7 (or 20) boxes? Do you have better ideas? Great – let us all know.

Or, write the book, register the copyright, and then tell us about it!

Kevin G. Chapman is a full-time attorney and a part-time crime-fiction author. His current Mike Stoneman Thriller series has been recognized for excellence in the Kindle Book Award and the Chanticleer International Book Award competitions. His  most recent installment, titled Fatal Infraction, released in July 2021.

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