Murder mystery movies operate on a delicate balance between formulaic and unpredictable. The genre isn't usually defined by its setting or imagery in the same way as science fiction or westerns might be. Instead, following familiar plot beats can be the most satisfying part of any given murder mystery.
Some of these tropes are so familiar that they have been twisted and parodied to death, with films like Knives Out, Clue, and recently the Disney Plus series Only Murders in the Building deconstructing them for comic effect. These tropes can still be enjoyable in dramatic settings though, so here are some examples that are riveting whether played for laughs or gasps.
Updated on December 27th, 2022 by Colin McCormick: With Glass Onion: A Knives Out Mystery hitting Netflix, fans get the welcome return of the murder-mystery franchise. What is fun about Rian Johnson's whodunnit movies is how they use the tropes of the timeless genre to great effect, keeping the audience guessing. And with such a long history of these types of movies, there are so many more common tropes from murder mysteries that fans will surely recognize.
A Mysterious Injury
This trope isn't unique to murder mysteries and covers all sorts of genres where characters will explain away mysterious injuries as an unfortunate accident. Mysterious injuries can raise questions about certain suspects in a murder case, potentially being an accident sustained during the act of murder.
In the first season of Fargo for example, Lester Nygaard picks up an injury from a murder he was involved with, and the wound becomes totemic of his morals slipping away as it festers over the course of the series. Wounds can be metaphorical but also frequent red herrings to mislead the audience, although they may not always be instantly associated with the murder mystery genre.
The Keen Detective
Despite the huge all-star ensembles of Knives Out and Glass Onion, Daniel Crag's Benoit Blanc is the real star of the show. He is a brilliant detective who is prone to messy analogies, but few things slip by his detection. He seems to relish the fun of cracking the case.
There are other Zodiac's Robert Graysmith.
The Absent Murderer
Keeping the eventual murderer absent from the main action of a plot is a useful trope in keeping the audience from guessing too early on. This is notably used in Knives Out where Ransom, the eventual perpetrator, is offscreen for a significant portion of the film while his family are grilled by Detective Benoit Blanc. It's a careful balance, however, as this kind of plot twist can make the audience feel cheated, with no real opportunity to guess who committed the crime until late into the narrative.
Lights Off
While not necessarily needing to involve literally turning off the lights, this trope usually involves a reversal of fortune for the detective. A lights-off murder in a crowded room is typically used to shock the audience, and can also hinder progress made by the detective so far.
This trope is often parodied in slapstick films and cartoons but also has a significant dramatic effect. Sometimes the lights go off right before a crucial piece of information is to be revealed, leaving the detective at square one. Clue utilizes this trope in an over-the-top manner during the death of Mr. Boddy, where the lights go out as an opportunity for him to fake his own death.
Premature Suspect
While most murder mysteries will inevitably build to the reveal of the killer, there is always an initial accusation that doesn't pan out. A suspect who seems like the most obvious choice will be accused only for some new piece of evidence to exonerate them.
surprising horror movie villain reveal.
Everybody's Guilty
One typical conclusion to a murder mystery narrative involves outing more than one, if not all, of the suspects as murderers. This trope can be effective in undermining audiences who may be expecting a single perpetrator, however, it can be overwhelming to keep track if a narrative starts to overflow with several victims, murderers, and motives.
This can be played for laughs as in the absurd third ending of Clue where all but one of the main cast are revealed to have murdered at least one person. This kind of reveal can also work in serious murder mysteries like Gosford Park where one character is exonerated for the murder since he stabbed a victim who had already died from poison.
The Unsympathetic Victim
Often used to complicate matters, having an unsympathetic victim in a murder mystery is used to create several suspects with viable motives. While not present in many murder mysteries, it's famously used in The Simpsons' murder mystery parody 'Who Shot Mr. Burns?', in turn riffing on Dallas' famous 'Who Done It' episode.
The first part introduces several motives due to Burns' increasingly hostile behavior towards the people of Springfield, and this is quite effective in muddying the waters when determining who the perpetrator is. This trope can also be used with multiple potential motives to murder, leaving the audience to piece together which one is most plausible.
The Faked Death
When the clues don't quite add up and there's no body to be found, sometimes the murder might be a set-up all along. This trope may technically disqualify the film from counting as a murder mystery, due to no murder taking place, but is still a common enough twist in the genre.
The faked death turns up frequently in film noir, with examples like Gone Girl and The Third Man both utilizing the devilish twist in their narratives to pull the rug from under the audience's feet.
In Plain Sight
Part of what audiences love about murder mysteries is attempting to solve the case along with the detective. Some of the best movies in the genre help viewers do this by hiding clues and revelations in plain sight that seem so obvious when rewatching them.
Martin Scorsese's movie that feels like a puzzle, dealing with a detective searching for a missing inmate at a psychiatric facility. When it is revealed the detective is actually an inmate, the audience can see the answers staring them in the face the whole time.
