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Locked Room Mystery

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"His lordship must have strangled himself by surprise!"
"The door had been locked from the inside. The windows were barred, locked from the inside, didn't open and were made of brick. All the books were chained to the shelf save one, open on the table at a page entitled 'How to secure a room from the inside'. All the boxes had been ticked. And even the pen used to make the ticks was one of those ones on a little chain you get in banks."

A seemingly impossible crime, the standard example being that of a murder victim found in a room with only a single door, securely locked from the inside. Can be the basis for a single plot, or an entire show. A well-designed Locked Room Mystery provides pleasure from trying to figure out the puzzle before it is revealed, from moments of dawning realisation, and from a satisfyingly logical solution. A poorly designed Locked Room Mystery only provides a feeling of having been cheated. Contrary to the name, Locked Room Mysteries don't necessarily have to be murders or take place in locked rooms, just to be crimes that seem to be impossible at first glance (e.g. contemplating how it's possible for someone to travel from one part of the island to another within minutes). The question of who is rarely as interesting in this kind of plot as how.

Originally from crime fiction, John Dickson Carr being an acknowledged master. It is noteworthy that Edgar Allan Poe's short story "The Murders in the Rue Morgue", widely considered to be the first detective story, involves a Locked Room Mystery.

Appears on television in a number of forms. The relatively pure form as a sub-genre of crime television (e.g., Monk, Jonathan Creek) where the puzzle is eventually unraveled by an eccentric protagonist using subtle clues and pure reason.

The part of the show where the solution to the mystery is explained is The Summation. One common trick used is the Time-Delayed Death — for others see the Analysis page. Expect the police to have found that The Key Is Behind the Lock when the crime scene was discovered. If a murder victim turns up someplace that's just so weird it's hard to explain, that's Body in a Breadbox.

Compare Fakeout Escape where somebody held captive invokes this trope to escape from the room.


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    Anime & Manga 
  • The 2003 Astro Boy show has an episode in which notorious gangster Skunk Kusai is suspected of several bank heists where the vaults were tunneled into, but examination reveals the holes to have been dug from inside the vaults and the doors were never tampered with. It turns out that he had kidnapped the inventor of a powerful electromagnetic device and used it to rearrange all the gold in the vault into the shape of a giant robot centipede, making the loot dig itself out and deliver itself to him.
  • One of these comes up in Black Butler. It turns out to be a prank by the Queen and Ciel playing The Chessmaster to deal with a target of his.
  • Case Closed frequently uses these, though it also plays with this trope, as Conan solves a case when he realizes that a man died the moment his wife checked on him (he was drugged into sleep until then), but the rest of the room was set up to make it look like a locked room mystery.
  • Commonplace in Detective School Q. The solution generally involves some manner of sealing the room from the inside in some way that can be performed while outside the room or committing the crime from outside the room. One example is in a case when two idol siblings were suffocated, one to death while another one in critical condition in a small room with no way in or out. Their rooms were covered by a gigantic advertisement rubber balloon which could fit the whole room. The reason the second victim survived was because she didn't turn off her room's light before sleeping (she was terrified of ghosts and drowsy after taking allergy meds), burning the rubber from its heat; Kyuu and Sakurako noticed the smell, found the almost dead girl and managed to save her. An example of the second was a man who was found dead in his home with the only door — which opened in — being blocked by a slab of concrete. The killer used a hose to pump the concrete into a mold from a window. The method of death involved fire, which destroyed the mold after the cement set.
  • Lampshaded in Domu, where the detectives have to investigate a series of suicides at one apartment complex. One man jumps off the roof to his death, despite the lock of the door to get onto the roof being rusted shut for years on end. The younger policeman points out how ridiculous this "sort of... locked roof mystery, right?" is. Too bad science can't explain it.
  • One of these pops up in Franken Fran to a group of former patients of Fran, with Okita specifically calling it by the trope name. The solution is a lot squickier than some of the other answers. The patients did it to themselves because they get off on Fran operating on them.
  • Golgo 13: In "The Serizawa Family Murders", two witnesses (brother and sister) to an old murder agree to a meeting in a hotel room guarded — but not under surveillance — by the police. They go in, but when the police storm the room after several hours, only the brother is in the room, denying that he ever saw his sister that evening. Despite being the prime suspect, they have to release him because they never find even a trace of the sister's body. "Down the toilet, one by one." The sister fatally wounded herself and told her brother — the murderer in the old case — how to systematically butcher her body to hide the evidence, if he didn't want to confess.
  • The Kindaichi Case Files features one in majority of the stories.
  • In Phoenix Wright: Ace Attorney (2007), "Turnabout Showtime" is referred to as "the world's smallest locked-room murder", as Flip Chambers is somehow fatally stabbed inside his Sparklestar costume, which cannot hold anything in its hands and is impossible to open by the wearer (although it comes to light that there are workarounds for that, such as catching the zipper on a piece of wire, or wearing the costume backwards).
  • One of the Detective Cilan episodes of Pok√©mon the Series: Black & White. Despite the door being locked and the outside being guarded by a Watchog, and the jewel under lock and key, the power goes off and the Liepard's Eye is stolen. Several clues point to Red Herrings, but Cilan eventually covers the truth: the man Ash battled in the tournament earlier in the episode purposely used an Electric type in their match to short circuit the power to cause a distraction, and had his Vanillite sneak into the room through a vent, make a key out of ice, and steal the jewel. The perp's role in the tournament would also serve as an alibi, since he'd be too busy battling Ash to steal the gem.
  • Although it is not a crime series, Spiral has a number of locked room mysteries that the protagonist must solve, including one literal locked room murder.
  • In one episode of Super Sonico, Sonico is found unconscious inside her locked dressing room with her guitar missing, and her bandmates, with the help of a Kid Detective, have to try and uncover who did it and how. Subverted when it turns out that that the room was never locked in the first place; the culprit just pretended it was in order to throw everyone off.

    Comic Books 
  • Avengers Inc.: The starting mystery has six supervillains all simultaneously killed in their cells, with audio picking up someone declaring "justice is served!" before shooting them in the head, but no visual trace. It helps if the killer can be smaller than the human eye, and if there's more than one of them.
  • There's one featured in Batman #700, in which the significantly aged corpse of Carter Nichols is found dead in his basement. Batman and Robin are unable to solve the case, but it is later shown that the present Carter Nichols went forward in time and killed his future self, causing his dead future self to return to the present.
  • The central case in Bookhunter involves three concentric locked room mysteries: The thief entered a locked library, removed a book from a locked safe, and carried the book out past the alarm checkpoints—leaving so little evidence that the theft wasn't noticed until weeks later.
  • Cable & Deadpool has one on Cable's island, where a former terrorist was murdered. There are almost no clues, and only three footprints on the floor. Irene wonders how someone could have gotten in and killed the man with only three footprints... only for Deadpool to instantly demonstrate how it's possible for a good enough merc. In fact, as more clue emerge, it seems Deadpool may be a prime suspect. The twist is that Deadpool is the one who did it, but he doesn't remember doing it due to his mental issues and has no idea why besides perhaps that he might have felt like it.
  • Disney Mouse and Duck Comics (especially the former) occasionally feature some versions. Unfortunately, it's poorly executed much of the time; if it seems the crime could only have been committed by a thief who could turn invisible, it's likely that's exactly what they did somehow, using a gadget or magic spell. However, there do exist some decent stories that feature an actual mystery of this sort as well.
  • Grandville: Bete Noir has a man killed in his locked study while checking his "pneumail" (phonographic message cylinders sent by pneumatic tube). An automaton was disguised as a pneumail cylinder, only activating when the cylinder was being read, killing the person in front of the machine, and then returning to its hidden state.
  • Identity Crisis (2004) begins with the locked room mystery of Sue Dibny. It ultimately leads to a lot of characters playing with the Idiot Ball since they live in a world with numerous teleporters, time travelers, magic users, et cetera. Essentially, it's something that doesn't work in a superhero universe if the characters actually act in character.
  • In Jon Sable, Freelance #44-45, Jon is present is on board a yacht when a movie star seemingly commits suicide inside his locked cabin. Of course, it is Never Suicide, and Jon turns detective to work out what really happened. The victim had been given poisoned Dramamine by his murderer which he took inside his cabin and died. A second person, looking to protect the killer, had used a bang stick to fire a bullet into the victim's head through the portal, hoping the police would not check for poison when there was an obvious gunshot wound to the head.
  • A staple of The Maze Agency comic book series.
  • The Tintin comic "King Ottokar's Sceptre" features a non-murder version of this; the sceptre of the King of Syldavia, regarded by the country as symbolic of the king's right to rule, has vanished from a room that was locked from the inside, with all four people inside having been rendered unconscious for a short time by a gas bomb planted inside a camera, bars on all windows, and no way for an accomplice to have just retrieved the sceptre if someone simply dropped it out of the window as the castle is surrounded by a moat and the loyalty of all guards in that area is without question. Tintin eventually deduces that the camera held a small spring-gun that was used to fire the sceptre out through the bars and into a forest on the other side of the moat.
  • A murder committed in a locked room would have been part of the plot in Alan Moore's never-written The Twilight of the Superheroes. Of course, it's easier to do in a world with superheroes, including some who can turn invisible and intangible.

    Fan Works 
  • In The Empty Turnabout, Arts was killed in his study, and the witnesses found only the defendant inside when they broke in. There is only one door to the study, and the room has a balcony that looks over an endless abyss. It's Apollo's job to figure out how anyone other than the defendant could have entered, killed the victim and escaped without leaving traces.
  • In The Parselmouth of Gryffindor, the overnight disappearance of Professor Igor Karkaroff, who had been hiding out in the extremely protected Iron Tower of Durmstrang Institute.

    Films — Live-Action 
  • This is a plot point in 3-Iron, as the hero uses some sort of stealth technique to fool the prison warden into believing he wasn't actually there in his cell.
  • Played with in Blood Simple, as the female lead disappears from a bathroom without a trace.
  • We don't learn how Eli escaped from his cell in The Book of Eli. The room wasn't locked but guarded.
  • In The Crime Doctor's Courage, Gordon Carson is found shot dead in a locked room with bars on the windows in what appears to be a case of suicide. It isn't suicide.
  • The Hateful Eight effectively becomes this after it's revealed that someone in the haberdashery is in on the plot to free Daisy, and even more so after the coffee is poisoned. The room isn't technically locked, but the door is in such shape that no one can enter or leave the room without everyone else in the building knowing it.
  • To some extent, I, Robot fits this trope: Dr. Alfred J. Lanning's death looks like an open-and-shut suicide because the door to his room was locked. Spooner, of course, thinks otherwise. This is correct, incorrect, and a major Batman Gambit/Thanatos Gambit on the part of the victim all at the same time. The killer, Sonny, is a self-aware robot whom Lanning ordered to kill him knowing that Spooner would likely catch the case, and that Spooner hated robots enough to keep digging until he uncovered the Big Bad's plot. Sonny was still in the room, in standby mode, when the police arrived.
  • Inverted in Law Abiding Citizen, in that Clyde is somehow pulling off elaborate murders while locked in solitary confinement. He had an escape tunnel.
  • This is a major plot point in The Shawshank Redemption, as Andy spends years digging a getaway tunnel through the wall of his prison cell. His escape leaves the wardens dumbfounded until they find the tunnel entrance behind a movie poster stuck to the wall.
  • In The Sleeping Cardinal, Roland Adair is found shot through the head in his locked study in what appears to be a suicide, except there is no gun.
  • In The Verdict 1946, Sydney Greenstreet plays a Scotland Yard inspector forced to retire after his investigation sends an innocent man to the gallows. Soon after that the nephew of the victim in the first case is found stabbed to death in his bed in a locked room that Greenstreet had to force open. Actually, the man was still alive (but drugged) and Greenstreet stabbed him to death after forcing open the door. He covered his actions by screaming that the man was already dead, causing the landlady to recoil in horror, missing his actions. The Inspector murdered the man for two reasons. First, he realized that the man had murdered his aunt for her money and let an innocent man hang for it. Also, he hoped that his arrogant successor at Scotland Yard would never solve the case, humbling him. In the end he had to confess to the crime to prevent another innocent man from being hanged for murder.

Examples by author:
  • John Dickson Carr, the acknowledged master of this back in the golden age of crime fiction, provided all sorts of different ways to accomplish this. In his book The Hollow Man/The Three Coffins, series lead Dr. Gideon Fell actually gives a lecture on the different ways a locked room mystery can be created. If the detective is Fell, Sir Henry Merrivale, or Henri Benicolin, there is an excellent chance you've got a locked room or impossible crime on your hands. The solutions range from puzzles of timing (e.g. the victim was killed earlier, and the body carried into the locked room by the person who claimed to have found it) through illusions (e.g., where there appeared to be two people, there was actually one person and a mirror) to technological or scientific tricks (e.g., there was a block of dry ice hidden in the room that would start turning into gas when it got cooler in the night, leading the victim to wake up to a feeling of suffocation, panic, and cause their own death) and everything between and beyond.
Examples by title:
  • The murder in Gilbert Adair's Agatha Christie pastiche The Act of Roger Murgatroid (whose title itself is a pun on Christie's The Murder of Roger Ackroyd) is of the locked room variety.
  • One of the "girls" disappears from a third-floor room in The Alienist.
  • And Then There Were None uses a "stranded on the island" variant of this trope: the ten people invited to the island were all trapped there by a storm and killed off one by one. When the police investigate, they find that the final people alive on the island couldn't have killed each other: one body is found drowned but pulled up past the shoreline, so someone must have been there to get move the corpse, and another is discovered hanging from a hook in a bedroom, but the chair that was kicked away to spring the noose has been carefully placed against the wall, meaning someone was still alive after that death. It turns out that the real killer faked their own murder to hide beneath suspicion, watched the final members of the household turn on each other and complete their work, then tidied up after the victims and arranged their own suicide to correspond with the written records of how they supposedly died the first time.
  • In Another Note, all five of BB's murders occur in rooms locked from the inside, which confuses the detectives endlessly as, according to Naomi, this is usually done to make a murder look like a suicide, and these were all obvious homicides. At the end, it is revealed that BB set up the locked rooms to make a suicide look like a murder, effectively framing his death on himself. As Ryuzaki points out, the mystery could be solved by assuming that the killer has a key to each room. However, that doesn't turn out to be the case; Ryuzaki had been trying to lead the investigation astray.
  • Beau Geste:
    • The Blue Water sapphire disappears in a room where nobody is except the six relatives of its owner when the lights go out for about twenty seconds. No one else could have entered the room without letting light in by opening the door.
    • When a relief column arrives at Fort Zindernuef, they see scores of dead soldiers propped up on the walls, and then someone shoots at them from inside the fort. One legionnaire enters the fort with a grappling hook but never reappears, causing his commander to climb after him. In addition to the bodies slumped against the wall, the commander finds a sergeant who was stabbed to death, and Beau Geste, who was laid out peacefully after the sergeant was stabbed and is holding a letter confessing to the theft of a jewel. The commander searches the fort and finds no sign of the scout he sent or whoever shot at him. When he goes to open the gate for his men, Beau and the sergeant's bodies and the letter all have disappeared by the time he gets back. Then as soon as they've left the fort, someone still inside sets fire to it. The commander is left musing that his superiors will think he's crazy when he describes everything that happened. The climax reveals that the man who shot at him, John Geste, went over the wall on the opposite side of the fort right after shooting at the approaching legionnaires, as he wants to desert. The scout who first entered the fort is John and Beau's brother Digby, who found the letter and then slumped over the wall, pretending to be one of the dead soldiers, when his superior entered the fort. When his superior went to open the gate, Digby dragged the bodies to a room the commander had already searched to give Beau a Viking Funeral and prevent him from being posthumously branded as a thief. After setting the fire, he then escaped over the opposite wall himself.
  • Rita Yarborough investigates one in the short story "Behind Locked and Bolted Door" in J.T. Edson's collection More J.T.'s Ladies.
  • Ben Snow: In "The Phantom Stallion", an invalid confined to a bed is murdered inside a room with the door latched and the window locked. The killer used a chip of ice to hold the latch open as they closed the door. When the ice melted, the latch fell into place.
  • The original locked room mystery is the C. Auguste Dupin story "The Murders in the Rue Morgue", which became the Trope Codifier for later detective murder mysteries. In the story, a corpse is found inside a room locked from the inside. Several witnesses hear voices of a suspect as they approach the room, but the killer is nowhere to be found when the room is opened. The only other possible means of escape are a chimney (which is too narrow to admit a person) and two windows (each of which was not just locked, but also held closed by a nail, which would be impossible to replace from the outside). It turns out that the killer escaped through a window. There is a hidden spring which automatically locks the windows whenever they're closed. Furthermore, the nail on one window is rusted and in two pieces, so it doesn't actually hold the window down. However, the police never bothered to examine this window closely after trying and failing to open the other one.
  • A non-murder example in in the sci-fi Change War novel The Big Time; the trope is referred to practically by name, as chapter 9 is titled "A Locked Room" and includes a quote from the detective story The Purloined Letter. The mystery involves the disappearance of a device which maintains the life support within an inescapable hyperdimensional location; it must be inside, seeing as everyone are still alive and there was no possible way to remove it from the area, yet it's nowhere to be found, even when the place is searched top to bottom.
  • The Chinese Orange Mystery by Ellery Queen has exceedingly weird clues, including the fact that the murder victim is found with his clothes on backwards. It's also not presented as a locked room mystery because doing so would have actually given away the killer's identity immediately.
  • "Death In The Dawntime" by F. Gwynplaine Macintyre was written specially for The Mammoth Book Of Historical Detectives, and probably has the earliest setting ever for a detective story. It's a Sealed Cave mystery.
  • In the first installment of the Max Liebermann Papers by Frank Tallis, A Death In Vienna, the murder is committed and discovered in an actual Locked Room scenario.
  • Discworld:
    • Parodied in "Theatre of Cruelty" when Vimes's Internal Monologue brings up the complaint that "wizards made locked room mysteries commonplace" (though there are never any actual examples of this happening in the series).
    • In Feet of Clay, the ultimately non-fatal poisoning of Lord Vetinari is a completely fair locked room mystery. In an interesting twist, the victim figures it out long before the "detective" does, but lets him do his job anyway.
    • A minor plotline of The Last Continent involving the folk hero "Tinhead Ned" has him managing to mysteriously escape the prison. As it turns out, the jail door isn't affixed properly, allowing him, and later the main character Rincewind, to lift the door off its hinges and escape without detection.
  • Author Baynard Kendrick (first president of the Mystery Writers of America) wrote a series of novels about blind detective Duncan Maclain. Most of the murders were clever impossible murders — a man stabbed in front of dozens of witnesses during a nightclub show, a man driven down a mountain road to his death while the murderer was miles away, and the like. The true locked room murder was a writer shot at his desk on a large balcony outside his Manhattan apartment while there was no one nearby. The gun was planted in a bush under which his dog liked to hide. When the church bells went off across the street, the dog dove for cover, triggering the gun.
  • Encyclopedia Brown has a non-lethal variant in one case. A wealthy former polar explorer's money is stolen. The man liked visitors and so it was easy for someone to visit his house, but he recognized that someone might want to rob him, so there's no way for anyone to exit without being thoroughly searched. The culprit brought several stuffed penguins along with him as a gift, hid the money in them, and then left, disguising the penguins as part of an exhibit on the man's adventures. When the man later died of natural causes, his possessions were to be auctioned off, so the robber planned to attend the auction and bid on the penguins so he could retrieve the money. The clue here is that the explorer had explicitly only visited the north pole in his adventures, while penguins only live near the south pole.
  • Evil Under the Sun involves a bunch of suspects, all with airtight alibis. Naturally, the solution involves a bath, a bottle, a watch, and a bathing cap. Two people were in on it; one to kill the victim and one to impersonate the corpse and make it look like the murder was committed earlier than it actually was.
  • Father Brown:
    • The Secret Garden has an inverted variant, where the murder victim somehow got in to an enclosed garden without anyone noticing. The murder victim was actually one of the guests who everyone thought had left. The murderer decapitated him, threw the head over the wall, and substituted it for the head of an executed criminal, making the others think that the man was a stranger.
    • "The Oracle of the Dog" features a man being somehow stabbed in a small summer-house which has no possible entry except the front door, which was under the eye of multiple independent witnesses from the moment the victim entered the summer-house to the moment the body was found. The solution turns out to be a Type 6 from the analysis page: the murderer snuck around the back and stabbed the victim through the latticework wall of the summer-house.
  • Happens in the Finnegan Zwake series with the man in Finn and Stoppard's storage room (in Horizontal Man) and Professor Freaze in his tent (in Worm Tunnel).
  • Forest Kingdom: In the Hawk & Fisher spinoff series' book 1, Councilor William Blackstone is found dead in his locked room, with a knife in his chest, and anti-teleportation wards preventing anyone from getting in and out that way. Later subverted when two of the suspects admit that one of them found him dead first, and locked the door afterward to make it look like one of these.
  • Most of French mystery author Paul Halter's works fall into this category. For example, in The Fourth Door, a man enters a supposedly haunted attic room. The door is sealed from the outside with a ribbon and wax, and the wax is imprinted with a rare coin chosen at random. When the cast enter the room later, still sealed from the outside, they discover a different man lying stabbed to death.
  • Fun Jungle:
    • In Poached, no one can figure out how anyone could have broken into the koala enclosure without setting off alarms, or without being caught on the security cameras. It turns out that the crime actually happened a day earlier, at a time when the door was unlocked, and Large Marge hadn't thought to check back that far.
    • In Panda-monium, no one can figure out how the thieves managed to break into a moving trailer truck and snatch the panda (and Doc Deakin). Actually, the driver drugged the guard, pulled over on the side of the road, then switched the trailer with another one furnished to look the same while his partners drove the actual one away somewhere else.
    • In Tyrannosaurus Wrecks, the T-Rex soul disappeared from the (very muddy) dig without anyone leaving footprints, during the middle of a storm which would have prevented anything like a helicopter from taking it. Actually, the theft occurred earlier than anyone assumed, using rollers to move the skull a very short distance then re-bury it to come back for later.
    • In Bear Bottom, Kandace's valuable necklace disappears from her room, and she'd been alone, behind a locked door except for a brief period where several people chase a rampaging bear inside. The culprit got in through a Prohibition-era secret passage.
  • In Christianna Brand's "The Gemminy Crickets Case", Giles obtained a policeman's uniform, killed his guardian and made a fake distress call to the cops so that when actual officers showed up and broke down the locked door, he could pretend to be coming into the room with them. He also broke a portion of the window and set the desk on fire to confuse the issue.
  • "Gimmicks Three": Using supernatural elements, the protagonist Isidore Welby has found himself locked into a perfectly cubical room, made from thick bronze. He is given the power to travel in any direction, and if he fails to escape before noon, he'll be a soul damned to eternal torment in Hell. The solution is to view time as a dimension, and travel backwards.
  • Gosick starts off in classic style, with the old lady shot through the eye in her locked room. Although it's a fairly simple mystery, this serves as a springboard for a whole ship-ton of intrigue in the next story.
  • Most of The Great Merlini's cases are some form of "impossible crime", with actual locked rooms common as well.
  • Amelia Bones's body was found in this fashion by the Muggle police in Harry Potter and the Half-Blood Prince. The police of course couldn't figure what happened, but the reader know that she was a wizard killed by the Death Eaters.
  • The Haruhi Suzumiya chapter "Remote Island Syndrome" has an example of this inside a locked room on an island hit by a terrible storm. The murder turns out to be an act put forward by the people on the island to entertain Haruhi.
  • Heralds of Valdemar: One Tarma and Kethry short story features a locked room mystery, with all of the locals assuming that the victim's wife was the killer, because she was the only person other than the dead man who had a key to the room in question. The real killer actually killed the victim before the door had been locked, and used a clever device to bar the door from the inside after he left.
  • In one arc of Hyouka, the Classic Lit club is called upon to help find a conclusion to a student film made with this plot due to the film's writer having to bow out of the project due to illness.
  • Irish Village Mysteries: Murder in an Irish Pub has poker player Eamon Foley found in the storeroom of a pub hanging from a rope. The door is locked from the inside and Foley seems to have a suicide note in his pocket. The killer locked the deadbolt by hooking a tentpole around it through a small window. The "suicide note" is actually an autograph Foley gave to a fan.
  • Jaine Austen Mysteries: A very minor one not related to the murder in Death of a Bachelorette. No matter what Jaine does (including getting a bolt installed on her door), her cat Prozac keeps escaping from her room on the island where the book takes place. It's revealed that she was escaping via a hole in the wall hidden from sight by Jaine's bed.
  • The Jonathan Creek episode guide includes "The Riddle of Castle Cain", a competition in the form of a locked room mystery in which the reader is given the same clues as Jonathan to deduce how a very overweight film director could be killed in his viewing room, when someone immediately looked through the projection window and saw no-one there, and he fell against the door making it impossible to open more than a crack. The solution: he was killed by his "waif-like" six-year-old stepdaughter. who hid behind a speaker and was later able to slip through the crack in the door.
  • In The King Is Dead (1952), King Bendigo is shot in an impenetrable sealed room, which only had one door, which was locked — and just to make it more challenging, the man who shot him was in a completely different room.
  • The trope is lampshaded in two Known Space stories featuring UN investigator Gil Hamilton, "ARM" and "The Patchwork Girl", though the latter story inverts the trope — the 'room' is a lunar city, and the suspect is the only person who was known to be outside on the Moon's surface at the time. Larry Niven wrote the stories to show that you could use this trope in Science Fiction.
  • The first murder in Lessons for a Perfect Detective Story is one. Tenkaichi lists how every single locked-room murder is created and that they're so popular because they're the riskiest yet most brilliant trick to pull off, not to mention how utterly tiresome he finds them. The one in this episode was caused by the old building becoming deformed when it snowed during the night, meaning the unlocked door became stuck. So the murderer made it appear as though they had barred the door, so when the police broke the door down it looked like it was locked from the inside.
  • In the Lincoln Rhyme novel The Vanished Man, the killer is seemingly able to escape from a locked room where one of his victims is found, as well as disappear into a small crowd.
  • In Elizabeth Peters's "The Locked Tomb Mystery", an ancient Egyptian reports that his family's crypt has been desecrated and robbed a year after his mother's lavish burial. A search reveals no evident means of egress, and the door's seal was unbroken when he and a friend came to check on the tomb. The sleuth who investigates the crime concludes that the woman's son had left a linen wrap on the tomb floor as a "mummy" during the funeral, then later brought his very nearsighted companion along to glimpse it lying there. While his friend was fetching the police, he robbed the tomb himself.
  • Intentionally played to the point of absurdity in The Long Dark Tea-Time of the Soul. Dirk Gently finds that his newest client, a wealthy man who had hired him as a security guard, had his head severed and placed on an active record machine while awaiting Dirk. Of course, the door to the room was locked from the inside when the scene was initially discovered. The police analyze this as an elaborate suicide done simply to cause trouble. In fact, magic was involved, but Dirk concocts a ridiculous but just barely plausible explanation of how it could be a suicide rather than try to convince them that magic is real.
  • Randall Garrett used this trope often in his Lord Darcy stories, with the added twist that magic is real in Darcy's world. Magicians naturally become prime suspects in a Locked Room Mystery, yet Lord Darcy often works out a non-magical explanation, thus exonerating some innocent wizard of the crime. The most notable is the man who was stabbed from outside the room through the keyhole (the door had an old-fashioned lock that went completely through the door and was large enough for a narrow blade to pass through).
  • The Mammoth Book of Locked Room Mysteries and Impossible Crimes, is a mix of classics of the genre and new stories adding modern twists:
    • "Murder In The Air" by Peter Tremayne (Sister Fidelma), where a man is killed in an aeroplane toilet.
    • "Ice Elation" by Susanna Gregory, where a scientist disappears from a locked lab, in an Eerie Arctic Research Station at the Pole of Inaccessibility.
    • A variation in "Proof of Guilt" by Bill Pronzini, where the victim and the killer are both in the locked room. When the door is opened, the victim is found to have been shot dead... but there is no sign of the gun. The police tear the room apart but come up with nothing. Even if the killer had stripped the gun down to its individual parts, they would still have been found. Under the circumstances the police have no choice but to let the killer go. Months later, when it is far too late to do anything about it, the detective in charge of the investigation solves the mystery: The killer was a circus performer billed as "The Man with the Cast-Iron Stomach". He did indeed strip the gun down to its individual parts... and then swallowed them.
  • The protagonist of the short story "The Man Who Read John Dickson Carr" by William Brittain murdered his wealthy uncle and escaped from the room through the chimney in order to confuse the inevitable investigation. It might have worked if he'd remembered to lock the door.
  • The Millennium Series novel Men Who Hate Women/The Girl with the Dragon Tattoo is about a journalist investigating a forty-year-old murder which is a Locked Room Mystery on an island. It's a subversion, though. The girl in question did live on an island, and she did disappear without a trace during a time period when the only bridge to the mainland was closed off. However, her uncle later admits that the family didn't realise that her disappearance could have been against her will until the bridge was already open again, and by then she and the abductor could have been long gone.
  • The Psych tie-in novel Mind Over Magic centers on the case of a costumed magician who appears to dissolve into nothingness in a water tank before a crowd of spectators but never reappears after the illusion, with a dead body suddenly in the tank in the magician's place.
  • Elliott Roosevelt, son of FDR, wrote a series of detective novels which cast his mother in the role of the sleuth. One of these, Murder In The Oval Office, is about the murder of a Congressman in the Oval Office after working hours. The murderer uses a simple trick to lock the door behind him in a failed attempt to make it look like suicide.
  • The Mysterious Mr. Quin: In "The Dead Harlequin", a wealthy lord is seen entering his study during a costume party, locking the doors behind him, and then shooting himself — but there was almost no blood in the room. It turns out that he was actually murdered earlier that evening in the adjoining chamber, and the "lord" passing through the party was actually the murderer disguised in his clothes; the gunshot everyone overheard at that point was simply fired into the wall, which already had bullet holes in it due the house's violent history.
  • The novel The Mystery Of The Yellow Room, by Gaston Leroux (better known as the author of The Phantom of the Opera) is a Locked Room Mystery that is also a perfect Fair-Play Whodunnit. The twist solution to the mystery, while being completely unexpected to the unprepared reader, manages to be on reflection the only logically possible solution given the facts of the case.
  • The Naked Sun has a very large-scale variant. The victim was murdered in his house, which was not locked, but still inaccessible to anyone except his wife due to Solarian social codes forbidding human contact (and in fact, the anthropophobia all Solarians have means that very few could bring themselves to violate this code to kill the victim in person) and the massive scale of Solarian estates meaning that no one could just casually walk over to visit (and none of the household robots saw anyone who wasn't supposed to be there). If the murder weapon hadn't somehow vanished, it'd be considered an open-and-shut case, but as we eventually find out, the wife isn't the murderer. She is, however, the killer. The true murderer was her friend and knew that she often fought with her husband, and so contrived to smuggle her a weapon when she was in a blind rage. She killed her husband in a momentary blackout and the murder weapon was inadvertently disposed of by cleanup robots before Elijah even got there, since nobody recognized it for what it was.
  • The Name of the Rose: The first death involves a defenestration beneath a window that cannot be opened, leaving the monks to suspect that supernatural evil is at work. Brother William easily proves that the man was a suicide who jumped from a nearby tower, and his body rolled to its final resting place. Unfortunately, this death is quickly followed by others.
  • Nick Velvet:
    • In "The Theft of the Venetian Window", Nick drugs the owner of the eponymous mirror by slipping sleeping pills into his coffee, then leaving and returning when the pills have had time to take effect. However, when he returns he discovers that someone has murdered the owner in the interval inside a locked room while Nick has been outside the only exit the entire time.
    • In "The Theft of the Overdue Library Book", Nick has to work out how Sandra Paris abducted someone from a men's room that had an Angry Guard Dog outside its only exit.
    • In "The Theft of the Bermudan Penny", the owner of the eponymous coin vanishes from the backseat of the car Nick is driving at high speed along a freeway.
  • Played with in the Nursery Crime book The Big Over Easy. "The entire crime-fighting fraternity yesterday bade a tearful farewell to the last 'locked room' mystery at a large banquet held in its honor. The much-loved conceptual chestnut of mystery fiction for over a century had been unwell for many years and was finally discovered dead at 3:15 A.M. last Tuesday." Then it turns out that the locked room mystery was murdered... in a locked room.
  • C Daly King's Obelists Fly High is a variant: the murder takes place on an airplane.
  • The first book in the Obsidian & Blood trilogy, Servant of the Underworld, involves one of these. A priestess vanishes entirely from a locked and guarded compound. The room she vanishes from? Covered in blood. But there's no blood trail leading out, and no one in the compound saw what happened to her...
  • Playback: The body of a blackmailer is found on the balcony of a hotel room. There's no way he could have climbed up to it, the room was locked, and its occupant didn't let him in (although, as one of his victims, she's afraid the authorities won't believe her on that point). It turns out that he fell to his death from the terrace of the hotel penthouse, higher up on the same side of the building.
  • The Poet and the Lunatics: "The Shadow of the Shark" is a variant that actually takes place in the middle of a beach — the locked-room element being that that beach shows absolutely no footprints other than those of the deceased.
  • Prague Fatale: Bernie Gunther, a detective in Nazi Germany, has to solve the case of a man who was shot to death in a locked room. He eventually figures out that the man wasn't dead, he was only drugged. Bernie's boss Reinhard Heydrich pronounced the man dead, then pulled out a pistol and shot him after everyone else had left the room.
  • One of the characters in the prologue to Roger Levy's Reckless Sleep is a fan of locked door mysteries, and has thought up a fairly elaborate one of his own which he gleefully shows off to an uninterested accomplice.
  • In Rokka: Braves of the Six Flowers, the main cast is within a forest when they become trapped there by a magical barrier covering the area, which is activated from an initially sealed room in the forest. The barrier goes up shortly after the seal is broken by the main character, and he then enters to find the room empty and the activation key already in place.
  • In "The Room in the Dragon Volant" by Joseph Sheridan Le Fanu, among the mysterious disappearances at the eponymous inn which the policeman Carmaignac relates to Richard Beckett, there is a particularly puzzling case of a man who vanished from his room between the late evening and the morning while the room was locked from the inside, and nobody could have left the building unnoticed. By the end of the story, it has become clear that the lodger was targeted by con men who induced him to leave his room by way of a secret passage, and then murdered him.
  • The award for all-time nastiness in a locked-room mystery has to go to Marjorie Bowen's "Scoured Silk". Mr. Orford (a nice man who keeps to himself) is engaged to young Elisa and takes her to visit the grave of his first wife Flora, a "wicked woman" who'd had an affair 20 years ago. The man was sentenced to hang; Flora died some weeks later. Orford shows off his "cabinet", a small study that immediately gives Elisa the creeps with its portrait of Flora, and a picture of a hanged man on the wall behind the desk. A tattered silk ball gown is draped over a chair.note  The housekeeper later confides that she's heard him talk to the portrait and then "imitate her voice, answering". Elisa, terrified, calls off the wedding. The next morning, Orford is found in the locked cabinet with a steak knife in his back. Fascinated despite herself, Elisa returns with her cousin and investigates, discovering a portion of the silk dress now caught in the panel behind the desk. It is a secret door. Three guesses what was in there and the first two don't count.
  • Sherlock Holmes:
    • The "canon" Sherlock Holmes stories provide several locked room mysteries, including "The Adventure of the Speckled Band" (the killer trained a venomous snake to get into the victim's room from an air vent), "The Adventure of the Empty House" (the killer was a sniper with a specialized air gun), and The Sign of the Four.
    • In the "non-canon" Holmes story "The Doctor's Case", first published in the centennial collection The New Adventures of Sherlock Holmes, Inspector Lestrade presents Holmes with something the detective has always dreamed of: a "perfect locked-room murder". However, as you might guess from the title (and somewhat to Holmes's chagrin), it's not him but Watson who spots the vital clue and cracks the case.
    • Sherlock Holmes and Doctor Was Not: In "The Locked Cell Murder", Holmes and Dr. Amelia Van Helsing investigate when a convicted murderer is found strangled in his locked cell on death row two days before he was due to be executed.
  • Teddy Daniels is brought to Shutter Island to investigate a locked room mystery — in this case, someone escaping from a locked and guarded room.
  • Many of the Simon Ark mysteries involve some kind of variation on the locked room mystery. The implication is usually that some sort of occult forces are involved. The reality inevitably turns out to be something much more mundane.
  • The Sword Art Online short story "Murder Case in the Area" is a form of locked room mystery involving players in an MMO where Your Mind Makes It Real being PKed inside a town, where game mechanics make it impossible to be attacked or injured. It turns out that they're actually faked suicides, with players stabbing themselves with weak weapons, then pretending to be attacked after some time and teleporting out to simulate game deaths. These players thus succeed in Gaslighting a former member of their group into confessing to the murder of a fourth.
  • The Thinking Machine stories contain multiple variants on the locked room mystery. "The Problem of the Grip of Death" is an excellent straight example where the victim is found strangled in his locked apartment, with the windows latched and the door not only locked, but barred in such a way that the bar could not have been dropped from the outside. The solution ultimately involves a boa constrictor acting as an Animal Assassin.
  • Several stories in The Thirteen Problems rely on this trope.
    • In "The Blue Geranium", a superstitious woman receives warnings that various flowers in her room will turn blue with each full moon. She is found dead in her locked room after the third moon has passed, and the titular blue geranium appears on the wall, suggesting that she had somehow been frightened to death. In reality, the woman's nurse was behind the murder—she replaced the victim's smelling salts with cyanide and put red litmus paper over a few flowers in the room. When the strong fumes of the poison hit the paper, it reacted and turned blue.
    • In "The Idol House of Astarte", a costume party turns deadly after the host is stabbed in a grove of trees by apparently supernatural means—there's no weapon in the wound or the grove, and only the other party guests were there, so no one could have slipped away. The victim actually tripped and fell over a tree root, and when his cousin — the murderer — rushed up to check on him, he took a knife from his "brigand chief" costume, stabbed him while his back was to the rest of the group, and then put the knife back on his belt before anyone saw what happened.
    • A non-murderous variant occurs in "Murder v. Opportunity". A rich man named Simon Clode is conned by a Phony Psychic and decides to leave almost all of his enormous estate and money to her. Simon makes out a will in full view of a lawyer and two witnesses; the lawyer then seals the will in an envelope and locks the envelope in his personal safe. A month later, when the envelope is opened, there is nothing but a sheet of blank paper inside. The mystery's title comes from the fact that two people had a motive to swap the wills — Clode's niece and nephew, who were the former heirs to the estate — but didn't have the opportunity to do so, while two others — the fake psychic and her husband — were left alone with the will and thus did have the opportunity, but no motive, as making the switch would disinherit them. It turns out that there never was a switch. Clode's other niece married a local chemist who, realizing that the psychic was gaining hold over Simon, prepared a fountain pen filled with invisible ink and gave it to the housemaid with the instruction to only use it if Clode said he planned on making a new will. She followed through, the text of the document vanished, and the proper heirs received their inheritance.

    Live-Action TV 
  • The first season of Altered Carbon is a Whodunnit to Me?, in which Laurens Bancroft was found dead in his own study, killed by a weapon to which very few people had access. Although he's obviously the prime suspect, he insists that he would never commit suicide and hires Kovacs to find the real killer. In fact, he did kill himself, but the situation is quite a bit more complicated than that.
  • The Andromeda episode "All Great Neptune's Ocean" has the President of Castalia be assassinated while shut in a conference room with Tyr Anasazi, while Tyr is shocked unconscious. The murder weapon is quickly shown to be Tyr's force lance, and Tyr had motive, having accused the President of war crimes against Nietzscheans, but Tyr argues that had he intended to kill the President, he would have used a less obvious method to ensure he wouldn't be caught — and he implies that has done exactly that in the past, so getting caught for this is ridiculous. It turns out that Tyr's weapon had been reprogrammed by the real killer to fire Homing Projectiles remotely, and Tyr was electrocuted by a failsafe system to prevent unauthorized use (the killer having overwritten Tyr's owner registration).
  • In the Astrid episode "Closed Room", a famously reclusive author is found dead in his locked apartment of an apparent suicide by cyanide, but nobody can find the poison bottle, which leads Astrid to suspect murder. The killer put the cyanide in the victim's ice cube tray and then just waited for him to use the cubes in his whiskey.
  • Colonel March of Scotland Yard: In "The Sorcerer", a psychoanalyst is found dead in a seemingly sealed room. Inspector March needs to decide who had the most reason to kill him, and how did they accomplish the task.
  • The Coroner: In "Napoleon's Violin", the Victim of the Week is stabbed to death inside a locked room.
  • In the first case of Criminologist Himura and Mystery Writer Arisugawa, a victim appears in a locked room while the witness was sleeping inside. Turns out that she had been killed beforehand and had her body rigged up with wire so that her killer could make her appear while the witness was alone in the room, implicating him of the crime.
  • One Crossing Jordan episode involves a man who was writing a book on vampires found dead in a locked room, drained of blood and with fang wounds in his neck. It turns out to be self-inflicted.
  • CSI:
    • A more diluted form sometimes appears, with the puzzle eventually being unraveled by an eccentric protagonist using more obvious clues and Forensic Phlebotinum.
    • One episode involves a murder committed where all the doors and windows were locked securely from the inside. The killer was a cable installer who unlocked a window to a hidden attic while working in the house.
  • Death in Paradise:
    • D.I. Richard Poole faces one of these in the very first episode. The solution was that it was technically a subversion: the victim didn't die until after the room was unlocked, and the witness was lying because she was the killer.
    • And again in "Hidden Secrets" in series 4. A surf instructor is shot inside a shed. The murder weapon is missing, the only door is locked and the wet sand outside the only window is completely undisturbed. In that case the killer ironically meant for it to not be a locked room mystery, but didn't quite get all the details indicating it wasn't a robbery gone wrong. The victim committed suicide,note  but tried to make it look like it wasn't one so the insurance would be paid out.
    • "The Impossible Murder" in series 6 uses a metaphorical locked room — the room wasn't locked, but the only ways the murderer could have gotten to the room can be excluded (the room was on the second floor, with the only stairs in Humphrey's field of view and thus him leaving able to vouch no one went up or down after the victim when the murder must have taken place, and while it would have been possible to climb up to or down from the window, it would have left visible disturbances that weren't there). So how did the murder happen? The victim was already stabbed when he walked upstairs — the people watching took his unsteady walk as the result of drinking — and did so to protect the person who'd stabbed him, knowing he did not have enough time to get to a hospital, but could have enough time to get upstairs, hide some of the evidence, undo the binding that impeded the bleeding, and bleed out in a seemingly perfect murder...
    • "Melodies of Murder" is a classic locked room mystery. A musician is found shot in his dressing room, the door locked and the gun in his hand. It looks like suicide, but an old fork on the floor and a missing guitar string make DI Mooney think otherwise. The murderer had killed the victim and staged it to look like a suicide. He then locked the door from the outside, and broke it open. He replaced the key on the inside of the door, then used the guitar string to pull the fork under the door, wedging it shut. When the police found the door seemingly locked, they broke it down, covering the damage the killer caused breaking it open.
    • "Switcharoo", the episode that introduces DI Parker, is one, with a woman found electrocuted by a hairdryer in a bathtub behind two locked doors in a hotel room. It doesn't look like one to the characters at first — Parker is there to sign off on it being a suicide as the woman was from Manchester — but then a niggling little detail about a mouthguard makes him refuse to sign off on it being suicide, which leads to him being dragooned into solving the case. The solution is that the entire scene of breaking into the room was staged in the room next to the one the murder took place in, with an accomplice in a wig who'd locked the doors behind herself playing the victim and leaving while the witness was sent away to call the police so the murderer could re-position himself by the room of the murder, which had been prepared to make it seem as if it had been broken into. With all the adrenaline and the rooms being both dark and practically identical, the witness didn't notice it wasn't actually the same room.
  • The Doctor Blake Mysteries: In "Room Without a View", the Body of the Week is found asphyxiated in a hotel room that has a chair jammed under the door handle.
  • The 1960s revival of Dragnet had a locked-room mystery in "The Big Bullet". A shooting victim was found dead in a room where the only door and window were locked from the inside (and the door barricaded by a chair as well). A recently fired .38 revolver was next to the body. Suicide was initially suspected because the man had a history of threatening to kill himself, but the crime lab discovers the bullet that killed him was a 9mm round fired from an automatic. It turns out that the killer shot the victim outside the room after he shot the book she was holding with the revolver, and the victim then went in, locked it up, and died.
  • In the season 3 premiere of Elementary, a witness in a drug case and the NYPD detective guarding her are both discovered shot dead at the bottom of a non-stop elevator ride from the hotel room serving as a safehouse. Sherlock, who had quit six months earlier, insists on being included because of the rarity of locked-room mysteries. The killer embedded several already-fired armor-piercing rounds in the elevator paneling and attached a powerful electromagnet to the opposite wall, which he then activated remotely to pull the bullets through the victims.
  • Ellery Queen: In "The Adventure of the Disappearing Dagger", Ellery must solve a locked-room mystery that occurred five years earlier in order to solve the current murder.
  • Father Brown:
    • In "The Curse of Amenhotep", the Victim of the Week is found alone in a room that was locked from the inside. It turns out that she was poisoned earlier. The poison caused hallucinations that made her lock herself in the room where she succumbed to the poison.
    • In "The Paradise of Thieves", the Victim of the Week is found locked inside a bank vault. Suspicion naturally falls upon the only person with keys to the vault. Father Brown believes him to be innocent and sets up to discover how this seemingly impossible crime could have been committed.
    • In "The Blood of the Anarchists", the first Victim of the Week is found slumped dead over his typewriter with a gun at his feet in an outbuilding with a window that doesn't open and a door bolted from the inside. However, Father Brown notices that there is not enough damage to his head for him to been shot with the gun pressed to his head.
  • Jonathan Creek is a show built around various sealed room mysteries (which feature in 13 of its 26 episodes to date) and other seemingly impossible crimes. A few examples:
    • In "Danse Macabre", a murderer carries a hostage into a sealed room. When the door is opened, only the hostage remains. The solution: the murderer was the hostage, in disguise, carrying a dummy. The dummy was cut up and stashed in the corner.
    • In "The Scented Room", a painting vanishes from a locked room during a school visit. The solution: a schoolgirl used the confusion of the school trip to ensure she was locked in the room, then simply stashed the painting in a hollow door panel.
    • In "Jack in the Box", a man is found dead in his nuclear bomb shelter, locked from the inside. Suicide...except he was arthritic and couldn't hold a gun. The solution: it was a Murder-Suicide — the murderer bricked himself into an unfinished wall and drugged himself to death.
    • In "The House of Monkeys", a scientist is found stabbed by a suit of samurai armor in his locked office. The solution: he was drugged by an Animal Wrongs Group, and while under its influence fell on the sword.
    • In "The Omega Man", the army seize what a prominent ufologist claims is an alien's skeleton. While locked in a crate to take it back to base however, it vanishes. The solution: the ufologist had made it himself from frozen mercury. Locked in the crate, it simply melted away.
    • In "Ghosts Forge", Jonathan's assistant vanishes from a locked room while investigating a mystery. The solution: to take him down a notch, she'd simply bribed a builder to plaster over a door in the room and hidden in there.
    • In "The Three Gamblers", the corpse of a dead criminal seems to have climbed the stairs from the cellar where the body was left and scratched at the door. The solution: flood waters moved the body, dumping it there when they receded.
    • Inverted in "No Trace of Tracy", where the prime suspect claims to have been handcuffed to a radiator in a room in his house at the time a girl was abducted. The solution: while unconscious, he had been carried to a replica of that room.
    • And one incident where the viewer knows the solution all along (the victim had been stabbed earlier but had been hiding the wound both to protect her mentally unstable attacker and so she could go on stage that night, only to accidentally re-traumatize the haphazardly treated injury by banging a piece of furniture against it and bleeding to death, whereupon a person who knew the truth, having found her first, hid the fake skin she'd used to conceal it from everybody else), but most of the characters don't.
  • In Kamen Rider Agito, the hallmark of a killing by the Unknown is that it is, by all rights, impossible — drowning in the middle of a field, being buried deep underground without any signs of digging, being entombed inside of a tree, your internal organs being ripped apart without the skin being broken, or falling to your death in a place where there's nowhere to fall from.
  • Los misterios de Laura:
    • A guy drowns in sea water while travelling on a plane, with several witnesses around who didn't notice anything strange- namely, he didn't drink a single drop of water, and nobody touched him during the flight. One of the attendants poisoned his chewing gum, and then bribed the forensics to add water inside his lungs while working on his autopsy.
    • Again in the TV-movie El misterio del asesino inesperado: a man is found dead inside his office, with a gunshot, but the weapon is nowhere to be seen and nobody is around. The door was locked from the inside and the windows were shut. He knew he had been poisoned and someone wanted to frame Laura's son, so he called Laura and told her he was going to lock himself, commit suicide with a non-immediately-lethal shot, throw the gun out the window and shut it. All she had to do was stand under the window to collect and then get rid of the weapon to complete the 'perfect' murder, which would both seem impossible to solve and distract from the poison, as the murder method was obviously the gun.
  • Monk doesn't usually have crimes that look totally impossible, just ones that look impossible for Monk's prime suspect to have committed. The prime suspect is always guilty anyway.
    • In "Mr. Monk Meets Dale the Whale", the eponymous Dale tries to avoid blame for ordering a murder by provoking a witness report that seemed to indicate he had done it personally, knowing full well the police will determine he couldn't have done it because he weighs 804 pounds and is bedridden. In this case, it was his physician (over whom Dale has blackmail dirt) who committed the murder and wore a fatsuit for the benefit of eyewitnesses.
    • In "Mr. Monk Meets the Playboy", the victim is a magazine publisher who died in an apparent accident while working out in a locked room. The killer was in the room below with a very powerful magnet, which he used to make the weight the victim was using fall on his windpipe and crush it.
    • "Mr. Monk and the Panic Room" has a traditional locked-room crime in an episode where a record producer is found shot inside a locked panic room which the police had to literally cut a hole in the door to enter, the only other living thing in the room being a chimpanzee who was holding the gun when the police came in. The security man who built the room had a secret entrance.
    • Steve Wagner was in outer space at the time of the murder in "Mr. Monk and the Astronaut", while Brian Babbage managed to commit murder while in a coma in "Mr. Monk and the Sleeping Suspect". Notably, both cases involved using the mail service as a time delay. The astronaut noosed his drugged victim to a garage door and mailed the opener to the house, the coma victim glued mail bombs to the insides of public mailboxes so they would be picked up days later. Brian Babbage also was originally planning to be arrested and locked up in jail when his bombs went off, but accidentally ended up in a coma.
    • "Mr. Monk Goes to a Rock Concert" has the same solution as the Death in Paradise example above with "Melodies of Murder". Namely, to give the impression that his victim overdosed in a port-a-potty, Kris Kedder uses one of his guitar strings to rig the lock so he could lock it from the outside.
  • Most of the first few seasons of Murder, She Wrote, being heavily based on Agatha Christie and Little Old Lady Investigates, were full of these.
  • These occasionally turn up in Murdoch Mysteries:
    • In "Houdini Whodunnit", a bank guard is found dead inside a vault secured by a time lock. Oh, and the vault has been robbed of a large amount of money too.
    • In "The Annoying Red Planet", Detective Murdoch asks Constable Crabtree why he was summoned to a scene where a man's body is hanging high in a tree. Crabtree draws Murdoch's attention to the lack of any footprints on the plowed earth for some twenty feet or so from the tree.
    • In "Big Murderer on Campus", a university professor is shot to death through a window, but the quadrangle where the shot came from was full of milling students at the time and no one saw a shooter.
    • In "Blood and Circuses", Station 4 has the entire surviving troupe of circus performers staying in the locked cells while the murder of the lion tamer is being investigated. One member of the troupe has a cell to himself and is stabbed to death in the night, and the weapon is nowhere to be found.
    • In "The Tesla Effect", a man is found dead inside a room with the door jammed shut with a chair. There's no obvious weapon, and aside from some curious blistering, no clearly fatal wounds. His body is later found to have been, as Dr. Ogden incredulously describes it, "cooked from the inside".
    • In "The Black Hand", a man is shot to death on a streetcar. The severity of the wound and the lack of a blood trail mean he couldn't have been shot anywhere else, but no one heard the shot.
    • In "Invention Convention", an inventor is shot in the head while accepting an award. The shot came from an impossibly high angle, and there were a dozen or more witnesses who saw no shooter.
  • The No. 1 Ladies' Detective Agency has an episode dealing with one that lampshades how it's just like a mystery novel plot.
  • Sherlock: In "The Sign of Three", a guardsman is stabbed inside a shower cubicle that is locked from the inside with no weapon inside the cubicle. As Sherlock puts it, they are looking for an invisible killer with an invisible knife who can pass through walls. Sherlock realizes at the end how the murder was committed: while taking a photograph with the guardsman, the killer stabbed him from behind through his military belt, worn tight enough to keep the wound from bleeding out. The injuries did not take effect until the guardsman had disrobed for his shower, hours later.
  • Star Trek:
    • A classic example is the Star Trek: The Original Series episode "Wolf in the Fold". A woman is murdered on a planet, and it at first seems obvious that Scotty is the killer. He's clutching the murder weapon. But then things start to get weird. After Scotty claims he can't remember what happened, the ruler of the planet suggests consulting his wife, who's an empath, and she gets strange visions of a great evil with a hatred of women, calling out several names like "Beratis", "Kesla" and "Redjac". Then the lights are cut, and she's killed too, again apparently by Scotty — although he said he felt something come between him and the seer. Eventually, the computer aboard The Enterprise discovers the truth, that "Redjac" is an incorporeal being that feeds on fear which has been behind several unsolved cases of serial killers on many worlds, including Jack the Ripper.
    • Star Trek: Deep Space Nine:
      • "A Man Alone" is a locked-room mystery, with the added twist that the only DNA found in the room is that of the victim and Odo, who is the investigating officer. This trope means that Odo is suspect, as he had a grudge against the victim and as a shapeshifter he could easily get into and out of a locked room. It turns out that the "victim" is actually the killer, and the body found is that of a clone.
      • In "Field of Fire", a lieutenant on the Defiant's flight crew is found in his room shot in the heart, with no sign of forced entry, or any entry at all. LTJG. Ilario was shot using a firearm that had been combined with a transporter that beamed its bullet to its target.
  • In The X-Files, the puzzle is typically subverted when an eccentric protagonist (Agent Mulder), on the basis of flimsy evidence and wild speculation, reveals that a Monster of the Week did it. In this case, the monster is the one using Applied Phlebotinum in the form of special monster powers. Two episodes in Season 1, "Squeeze" and "Tooms", epitomize this trope variant, with the monster managing to get at his victims in otherwise inaccessible places through his mutant ability to squeeze through tiny vents, windows, chimneys, et cetera.

  • MAD had a parody where a Sherlock Holmes pastiche finds a man lifeless on the ground of a locked room, and spends a page flying around laying out an elaborate series of events until the victim comes back from the dead to say that he accidentally hit his own head on the mantelpiece.


  • The centerpiece of The Adventure Zone: Balance's Murder on the Rockport Limited arc, in which the victim is beheaded and be-handed in a locked train car aboard a train which requires all passengers to surrender their weapons upon boarding.

  • John Finnemore's Souvenir Programme: One of the Storyteller sketches revolves around one of these, with a man found dead inside a one room building with no windows and the door locked from the inside. How did he get there? The killer built the room after killing him.

  • Potentially the Ur-Example, the Apocryphal/deuterocanonical tale of Bel and the Dragon from The Bible. Daniel sprinkles the floor of a temple to Bel with flour to prove that the priests of Bel were sneaking in through a secret entrance at night to eat the sacrifices each night, despite the temple supposedly being locked.

    Tabletop Games 
  • The Forgotten Realms module Four From Cormyr has a nobleman seemingly stabbed to death in his bedroom by a murderer he somehow didn't see coming despite looking in the mirror when he died, when the door is locked from the inside. The assassin picked the lock to the nobleman's bedroom and snuck in while he was preening in the mirror. She was invisible at the time, so he didn't see her coming up behind him. When he was dead, she locked the bedroom door from the inside and exited the room using a secret door leading out of the bedroom.
  • In Warhammer, Deathmaster Snitch killed an Imperial noble that had locked himself into a tower with the only door being guarded by a large band of knights. The knights didn't notice anything until the following morning. In fact, no explanation is ever given for how he did it, making it even more of a mystery.

    Video Games 
  • Detective Grimoire:
    • The case that Tangle Tower centers around is a Locked Room Mystery. A key complication of the case is that Freya and Flora were locked in the room when Freya died, and the door remained locked until Fitz kicked it down.
    • The Mermaid's Tongue also centers around one, with a submarine captain alone in a locked room save for a recently opened ancient stone cauldron.
  • Disco Elysium has one in the backstory. A man in a Hookah bar is found in a locked room dead. There is no sign of forced entry, no sign of a struggle. There is only a man, dead on the floor surrounded by cushions with a low table in the centre of the room. The first detective assigned cannot solve it, even as he tried every plausible angle he could think of, and a few implausible angles too. Eventually, he passes it on to the second detective, a pre-amnesiac you, who solves it in under an hour. Smoking a Hookah can disrupt oxygen flow. The man had smoked for an hour starving himself of oxygen, stood up, promptly passed out from the sudden vertigo, and broke his neck on the low table.
  • In Dragon Age: Inquisition, the player can find and read all of the chapters of Varric's in-game hit novel Hard in Hightown, which includes one of these as part of its mystery. Meanwhile, on the war table, a string of operations reveals that someone with a grudge against Varric is re-creating some of the murders in the story, including that one, and the Inquisitor's advisers must use their resources to figure out who it is. Although the guilty party is unmasked at the end of the quest chain, exactly how the locked room murder was done is never revealed.
  • The Elder Scrolls IV: Oblivion:
    • An interesting inversion of this trope occurs during a side mission; You and five other people are locked into a mansion on the premise that hidden somewhere in the house is a chest full of gold. Whoever finds it gets to keep it. A fun little game between friends, right? But soon, people start turning up dead, one by one, and suspicions fly as to who the killer is. Now, here's the twist; this is a Dark Brotherhood, a.k.a. Assassin's mission. You are the killer. The other five people are all targets, the mission is to kill them without them knowing you are the killer, and just for giggles, you're holding the only key to the front door. Oh, yeah, and there's no gold, either. Well, not for them, anyway. Unfortunately, it's programmed so badly that they never notice that you're the murderer even if you do it in front of them.
    • Another side quest, "A Brush with Death", is a textbook example; painter locks himself inside the study. His wife uses the only extra key to check up on him after he doesn't emerge for several days to find he is gone. It turns out that he's still in the room.
  • In one chapter of Ghost Trick, Lynne's corpse is found alone, in a room with only one way out that leads to several police officers waiting on the next floor. Of course, there's no real mystery to solve, Sissel just has to go four minutes back in time to find out what happened. She activated a Rube Goldberg Device murder machine, which was designed to kill anyone who turned on the lights and then destroy any evidence of its own existence.
  • In Paper Mario 64, Mario discovers the corpse of Mayor Penguin, with the name "Herringway" written on a piece of paper in his hand, in a room that, while it technically isn't locked, his wife was standing in front of the only entrance. Naturally everyone thinks Mario did it. He isn't actually dead. He merely fell and knocked himself unconscious while trying to retrieve a present for his friend Herringway from a high shelf.
  • In Paradise Killer, the eponymous murderer somehow bypassed an airless void, a need-to-know secret passcode, and a door that only opens for gods to get to the Council and murder them all. One of the culprits was smuggled in by a conspiracy beforehand, and the other had a secret passageway no one else knew about.
  • Dr. Schrader's death in Professor Layton and the Diabolical Box is one of these. Layton concludes that even though the office was too high up to exit from the window, the culprit did so anyway — by tearing off a curtain and fashioning it into a makeshift rope.
  • The Star Trek Online mission "What Lies Beneath" takes place in the dark maintenance areas of an old space station. The player party is near a locked room when they hear a cry for help from the intercom. After forcing the door, they find the still-warm body of someone who'd been shot with a phaser. One of your party members even wonders how someone was murdered in a closed room and how the killer got past them. The murderer is a malfunctioning maintenance hologram that later attacks the player. A mobile holoemitter is probably small enough to escape via air duct or similar passage.
  • Trauma Team's Forensics mode features a stage with this trope's exact name.

    Visual Novels 
  • Ace Attorney has a number of such cases, where the usual pattern is that a case seems straightforward to the police and the prosecutor because of the locked room, up until the protagonist finds some evidence suggesting otherwise (e.g., the victim being killed somewhere else, or the killer finding some way of smuggling themselves in or out of the room), usually before the end of the first day of the trial.
    • In Turnabout Samurai, the victim was killed in a closed film set, with the only entrance watched by cameras and a guard, who saw nobody enter, and the other part of the film studio was blocked by a fallen mascot head. Your client was the only person aside from the victim to be at the set, and he admits that his alibi (he was asleep) is rather thin.The victim was killed in the other part of the set, and his corpse was moved later by the killer. The guard saw nothing because she was only watching the entrance.
    • In "Reunion, and Turnabout", your assistant is locked in an empty room with the victim, a gunshot is heard, and the door is opened to reveal her standing over the corpse with a smoking gun in her hand. Naturally, it now falls on you to prove her innocent in court. The killer was impersonating your assistant.
    • "Turnabout Big Top" involves a man found dead in the middle of a snow-covered courtyard with only one set of footprints leading to the body... and an eyewitness who saw the killer leave the murder scene by flying over the rooftops. The killer dropped a heavy weight on the victim from a window; the "flying man" the witness saw was actually the murder weapon (a large bust) being reeled back up with a cape caught on it.
    • Doesn't look like this at first, but the fourth case in Ace Attorney Investigations: Miles Edgeworth turns into this when you deduce that a third person killed two men, armed them with a gun and a knife, and locked the room to make it seem like it was a mutual murder.
    • In Apollo Justice: Ace Attorney, there's a case where the killer has to have escaped from the room in the few seconds after Apollo and Ema heard the gunshots. Turns out the murder occured much earlier than when the gunshots were heard, which were actually firecrackers being ignited when Apollo and Ema were in front of the room.
    • "Bridge to the Turnabout" inverts the above pattern, with a murder that seemingly took place outside the "locked room", and the heroes have to prove that it happened on the other side of a bridge that burned down shortly after the deed and explain how the body was moved. Even the killer got trapped in the crime scene and then made it seem like he just arrived when the bridge was repaired and the police came, but you don't figure this out until late in the case.
    • Dual Destinies features a locked room in case two. There were two keys to the room, one of which was found in the locked room itself after the murder by police, and another was taken by a witness when she unlocked the door and found the scene. The defendant was found unconscious in the room, after it was unlocked. Therefore it was impossible for a third person to get out the room after they killed the victim, otherwise the door wouldn't be locked like it was. It turns out that the real killer killed the victim, and placed the unconscious defendant inside another room, which was thought to be unopenable by anyone other than the victim. Then, he disguised himself as the defendant using a wrestling mask, which the witness could not take off, as per masked wrestling protocol. Finally, after the witness left, he opened the second locked room, retrieved the defendant, disposed of the mask, and then left the room.
    • The second half of the fifth case of Spirit of Justice has the victim and the defendant found together inside a tomb. Of course, Apollo thinks the defendant is innocent, so the question is: who killed the victim and how did they come in and get out without the guards outside noticing? Simple: the murder occured one hour earlier than initially thought, when there were no guards watching the tomb.
    • The second case of The Great Ace Attorney Adventures features a murder inside a ship's cabin that was barred from the inside, with a message in Russian pointing to a wardrobe where Naruhodo was hiding as a stowaway. The ship's doors turn out to have a design flaw which causes the lock to slide into the locked position when the emergency brakes are activated, and everyone aboard the ship was given a sleeping drug to stop them from realizing this (and make sure they're sleeping in their rooms so they won't get locked out). Ironically, in this case, Naruhodo himself was subject to a locked room within a locked room, since there was a paper seal stuck over the door of the wardrobe he was hiding in, which would have fallen off if he left, and he couldn't have placed it while inside.
  • Locked rooms are a somewhat common scene in Danganronpa:
    • Danganronpa: Trigger Happy Havoc:
      • The fourth murder is presented as one of these, with the victim alone in a room with the door jammed shut to the point that the protagonist had to break open a window on the door to get it open. Eventually subverted; the victim committed suicide. The locked room was to prevent anyone else being blamed for her death.
      • Kyoko discusses the trope during the chapter 4 investigation, saying that locked room mysteries generally to fall into 4 types: The culprit found some trick to lock the room after leaving, the culprit set a trap of some sort that would go off on its own once the victim entered the room, the culprit remained hidden inside the room and escaped later after the room was unsealed, or the room wasn't completely sealed and had some secret way out.
    • Danganronpa 2: Goodbye Despair:
      • A variation happens during the third case, where, after Hajime Hinata is the first to discover a body in an otherwise empty building and leaves to fetch the other characters, the only entrance to the building is barred from the inside when he returns. After breaking down the door, a second victim is discovered, having seemingly appeared from thin air. In reality, the room wasn't really barred from the inside; rather, the killer, who returned to the scene of the crime after Hinata discovered the body and pulled the second victim out of hiding before he returned with help, had smeared an extremely strong adhesive on the inside of the double-doors on their way out, causing the door to seal behind them. To sell the illusion, the killer also placed a broken drumstick on the floor on the interior side of the door, making everyone think that the door had been barred shut.
      • The victim of the fifth case is found in a barred, burning room. Once the witnesses extinguish the flames, the victim is seen dead with numerous severe wounds all over their body. Adding to the mystery is that all possible suspects can corroborate each other's alibis. Turns out, it's a Type 7. The wounds are a Red Herring; they were self-inflicted (yes, the victim was kinda crazy, why do you ask?) but weren't what killed him. Instead, he had poisoned one of the extinguisher grenades the others used to put out the fires, so when the flames were extinguished, the poison got him. The culprit is ruled to be the one who picked up and used the poisoned grenade, but the characters have no way of telling which one was poisoned...
    • Danganronpa V3: Killing Harmony has three of these mysteries, two in a single case.
    • In the first chapter, the victim was found dead in a room that had cameras pointed at every entrance, and yet the the cameras didn't pick up the killer. This is actually a double-layered mystery; the person originally thought to be the killer had earlier created a death trap involving a vent that went from the classroom they were in to the library where the victim was, but the trap missed. The real killer took advantage of the cameras being unable to take another picture a short time after taking one, and emerged from a hiding spot right after the victim triggered the camera pointing there, killing the victim and returning to hiding (escaping via a secret passage) before the automatic camera was ready to take another photo.
    • In chapter 3, one victim is found with a stab wound through their neck, inside a room that was bolted from the inside. The killer stabbed the sword they'd used to kill her into a hanging sculpture of Kaede Akamatsu, then twisted the rope on the statue so that it would spin on release, the sword's hilt pushing the bolt shut. The other victim is somehow stabbed in the neck while crouching inside a cage, with a sheet and an 8kg statue on top, with several other people present. The killer rigged the floorboard the victim was crouching on to act as a seesaw, so she could be propelled upwards into the blade, which had been planted inside the cage.
  • Invoked repeatedly in Umineko: When They Cry, where it forms the core of the argument that the culprit must be the Golden Witch Beatrice instead of a human. But Beatrice is knowledgeable about the classics and doesn't stop here: she will abundantly shower the hero (and the reader) with red truths showing the perfection of the closed room and thoroughly wipe out any theory Battler may attempt. And on top of that, showing him (and the reader) fantasy scenes full of demons, magical barriers and Laser Blades. All while laughing. Of course, the point of the game is to not be fooled and find non-magic explanations. Bonus points for the first twilight of the third game: six people are found dead in six separate closed rooms, each victim having the key to the next room near their corpse.

  • The fate of the Val'Dutan'vir Ill'haressnote  in Drowtales. When their fortress was suddenly attacked by demons and Nidraa'chal summoners, Val'Dutan'vir forces succeeded in defeating them and not letting a single one reach even close to their clan leader. When they checked on their Ill'haress, they found her killed by her own guardian summon, who had somehow been tainted and turned into a demon. To this day, the survivors have no idea how their Ill'haress' guardian was tainted when no one should have been anywhere near the room.
  • Parodied in a League of Super Redundant Heroes one-shot. The Hercule Poirot expy says that all the characters had motive... and they promptly start pointing out that every one of them has a superpower that could have done it (teleportation, telekinesis, etc.).
    Not-Poirot: [exasperated] Calm down, it was the chef, he poisoned the cake. Locked-room mysteries just aren't the same anymore...
  • Schlock Mercenary has one in an arc that is an Affectionate Parody of CSI. The titular mercenary is found in a secured room with the corpse of the alien he was hired to guard, which was shot with Schlock's signature BFG, and no evidence of anyone else having been in the room. The solution is a Call-Back to an earlier arc, where millions of clones of various beings were freed. The alien's clone had been hired to kill his original. As a clone, he could bypass the biometric security and no evidence of a third person could be found. The clone managed to knock out Schlock, but the original managed to kill the clone, then dressed his dead clone in his own clothes so he could disappear.

    Web Original 
  • The Red vs. Blue episode "Grey vs Grey" features this, with a Deliberate Monochrome to give it that film noir appeal. (Also, to illustrate that all of the characters are colorblind) Essentially, a Red Team and a Blue Team unrelated to the main characters seal themselves in a room to broker a truce. The lights go out, a gun goes off, and one of the soldiers winds up dead and the rest need to figure out who shot him. The narrator reveals that the victim actually died of a heart attack before the shot was fired.
  • Reach's story (The Big Idea) in the Whateley Universe features one of these prominently. There's quite a bit of discussion about the ways in which one needs to examine such a mystery, before the final denouement happens more or less as expected.

    Real Life 
  • Arthur C. Clarke used a Locked Room Mystery in his descriptions of spatial dimensions: if two-dimensional beings had a "bank vault" sealed on all sides — i.e., a square — then a 3D thief could remove its contents via the third dimension, leaving the 2D police baffled.
  • On June 29, 1937, the body of Laetitia Toureaux was found inside a wagon from the Paris Metro. Nobody was ever charged with the murder, and it remain a mystery. There have been numerous speculations regarding the murder, including the secret service and La Cagout (a French fascist anti-communist terrorist group active from 1935 to 1941).
  • On March 9, 1929, police were called to the residence of Isidor Fink after hearing signs of a struggle. When they arrived, they found Fink dead of three gunshot wounds. However, the door was bolted shut, the windows were nailed down and the only fingerprints in the room belonged to Fink himself. The only way anyone would have gotten in was via a small window above the door but only a child could go through the opening. Someone firing through the window was also out of the question since Fink's wounds indicated he was shot at close range and that it was impossible for him to have shot himself (and the murder weapon wasn't found in the room). Motive was also unclear since even though it was a high crime area and Fink was extremely paranoid about getting robbed (hence all the extra security), none of his valuables were taken. No culprit was ever found and NYPD Police Commissioner Edward P. Mulrooney called the case an "insoluble mystery".


Video Example(s):

Alternative Title(s): Locked Room, Impossible Crime


The Murder of President Lee

"All Great Neptune's Ocean". Tyr Anasazi goes to apologize to President Sebastian Lee of Castalia for accusing him of genocide earlier in the episode, and out of respect, Lee asks everyone else to leave. The others chitchat for a bit, then Lee is heard yelling, and two shots are fired from a force lance. They rush back into the room to find Lee dead and Tyr unconscious.

How well does it match the trope?

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Example of:

Main / LockedRoomMystery

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