History Main / LockedRoomMystery

* In ''Literature/{{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.

** A non-murderous variant occurs in "Murder v. Opportunity". A rich man named Simon Clode is conned by a PhonyPsychic 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. [[spoiler: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.]]

* In ''Literature/TheKingIsDead1952'', 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.

* "Literature/DeathInTheDawntime" by F. Gwynplaine Macintyre was written specially for ''Literature/TheMammothBookOfHistoricalDetectives'', and probably has the earliest setting ever for a detective story. It's a Sealed Cave mystery.

** ''The Secret Garden'' has an inverted variant, where the murder victim somehow got ''in'' to an enclosed garden without anyone noticing. [[spoiler: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.]]

* ''Literature/{{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.

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

* On June 29, 1937, the body of [[https://en.wikipedia.org/wiki/Murder_of_Laetitia_Toureaux 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).

* ''Series/MastersOfHorror'': In the episode "[[Recap/MastersOfHorrorS1E7DeerWoman Deer Woman]]", what draws Faraday's attention to the trucker's death beyond the strange hoof prints on the victim's body is that the door to his truck was kicked out from the inside. While it's conceivable that the trucker could have been trampled to death by an aggressive buck, an animal of that size would not have been capable of the latter feat of SuperStrength, nor would a sufficiently large animal (like an Alaskan moose) been able to fit inside the truck to begin with.

* ''VideoGame/MasterDetectiveArchivesRainCode'':
** The Nail Man murders in Chapter 1 revolve around these as leaving the crime scene as a Locked Room Mystery is a CallingCard of the Nail Man on top of the nails in the victim and dolls everywhere. A key part of the investigation is figuring out how the crime scenes were set up which also provides clues to the Nail Man's identity.
** Chapter 4's murder takes place in a heavily-secured lab with plenty of deadly traps which only the victim could've turned off from his end if he's expecting a visitor, yet the culprit somehow bypassed everything and killed him.

* One of the Detective Cilan episodes of ''Anime/PokemonTheSeriesBlackAndWhite''. 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 Herring}}s, 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 [[ChekhovsGunman 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.

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[-[[caption-width-right:298:"His lordship must have strangled himself by surprise!"]]-]

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* Commonplace in ''Manga/DetectiveSchoolQ''. 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. [[spoiler:Their rooms were covered by a gigantic advertisement rubber balloon which could fit the whole room.]] The reason the second victim survived was because [[spoiler: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. [[spoiler: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.]]

* The first season of ''Series/AlteredCarbon'' is a WhodunnitToMe, 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. [[spoiler: In fact he did kill himself, but the situation is quite a bit more complicated than that.]]
* The ''Series/{{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 [[IfIWantedYouDead had he intended to kill the President]], [[MakeItLookLikeAnAccident 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. [[spoiler:It turns out Tyr's weapon had been reprogrammed by the real killer to fire {{Homing Projectile}}s remotely, and Tyr was electrocuted by a failsafe system to prevent unauthorized use (the killer having overwritten Tyr's owner registration).]]
* ''Series/{{Astrid}}'': "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. [[spoiler: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.]]

* One ''Series/CrossingJordan'' episode involved 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. [[spoiler: It turned out to be self-inflicted.]]
* A more diluted form sometimes appears in ''Series/{{CSI}}'' where the puzzle is eventually unraveled by an eccentric protagonist using more obvious clues and AppliedPhlebotinum.
** One episode involved a murder committed where all the doors and windows were locked securely from the inside. [[spoiler: The killer was a cable installer who unlocked a window to a hidden attic while working in the house.]]

** 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. [[spoiler: The victim committed suicide[[note]]the criminal of the week was his doctor who'd falsely led the victim to think he had an incurable degenerative disease, providing supposedly palliative medicine that provoked the symptoms[[/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? [[spoiler: 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...]]

** ''Switcharoo'', the episode that introduced 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.[[spoiler: 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 Sixties revival of ''Series/{{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. Turns out [[spoiler: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 "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: [[spoiler:it was murder-suicide - the murderer bricked himself into an unfinished wall and drugged himself to death.]]

* On ''Series/KamenRiderAgito'', 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.''
* The first murder in ''Literature/LessonsForAPerfectDetectiveStory'' 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 [[spoiler: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.]]

** "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. [[spoiler:The security man who built the room had a secret entrance.]]
** For "Mr. Monk Meets the Playboy", the victim was a magazine publisher who died in an apparent accident while working out in a locked room. [[spoiler: 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.]]
** Some episodes had Steve Wagner being 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". [[spoiler: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.]]
** 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.
** "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.

* ''Series/{{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: [[spoiler: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.]]

** A classic example is the ''Series/StarTrekTheOriginalSeries'' 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. [[spoiler: Eventually, the computer aboard ''The Enterprise'' discovers the truth, that "Redjac" is an incorporeal being that [[EmotionEater feeds on fear]] which has been behind several unsolved cases of serial killers on many worlds, including UsefulNotes/JackTheRipper.]]

*** Season one's [[Recap/StarTrekDeepSpaceNineS01E04AManAlone "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. [[spoiler:It turns out that the "victim" is actually the killer, and the body found is that of a clone.]]
*** In season seven's [[Recap/StarTrekDeepSpaceNineS07E13FieldOfFire "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. [[spoiler:LTJG. Ilario was shot using a firearm that had been combined with a [[{{Teleportation}} transporter]] that ''beamed'' its bullet to its target.]]

* ''Mad Magazine'' 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 Creator/MercedesLackey song "It Was A Dark And Stormy Night" features a death in a locked room to which there were only two copies of the key. One was found on the Countess' body, and the other copy was held by her HenpeckedHusband. After investigation showed that the Count had an airtight alibi for the entire night, backed by every servant in the household, the death was ruled as suicide (She tried to eat her lute). Reading between the lines, it's pretty clear that [[EverybodyDidIt The Count killed his wife, and everyone else in the household was in on it]].

* In ''TabletopGame/WarhammerFantasy'', 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.

** An interesting [[InvertedTrope 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; [[spoiler: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 [[spoiler:there's no gold, either. Well, not for them, anyway]]. Unfortunately, it's programmed so badly that [[spoiler:they never notice that you're the murderer even if you do it in front of them]].

* ''Franchise/AceAttorney'' 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 (eg, 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.[[spoiler: 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, [[CourtroomAntics it now falls on you to prove her innocent in court]]. [[spoiler: 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''. [[spoiler: 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.]]

** In ''VisualNovel/ApolloJusticeAceAttorney'' 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 [[spoiler: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]].

* {{Invoked|Trope}} repeatedly in ''VisualNovel/UminekoWhenTheyCry'', where it forms the core of the argument that the culprit must be the Golden Witch Beatrice instead of a human. But [[{{Troll}} Beatrice]] is [[ShownTheirWork knowledgeable about the classics]] and doesn't stop here: she will abundantly shower the hero (and the reader) with [[LanguageOfTruth 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 Blade}}s. [[https://www.youtube.com/watch?v=bnH9Gbw4ybk All while laughing.]] [[spoiler:Of course, the point of the game is to not be fooled and [[DoingInTheWizard 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 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. [[spoiler: Eventually subverted; the victim committed suicide. The locked room was to prevent anyone else being blamed for her death.]]

** 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. [[spoiler: 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 ''VisualNovel/TheEmptyTurnabout'', 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.

* {{Parodied}} in a ''Webcomic/LeagueOfSuperRedundantHeroes'' [[http://superredundant.com/?comic=604-murder-mystery one-shot]]. The Literature/HerculePoirot {{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...
* ''Webcomic/SchlockMercenary'' had one in an arc that was an AffectionateParody of {{Series/CSI}}. The titutlar mercenary was 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. [[spoiler: The solution is a CallBack 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 [[AssassinOutclassin managed to kill the clone]], then [[FakingTheDead dressed his dead clone in his own clothes so he could disappear.]]]]

* Reach's story (''The Big Idea'') in the Literature/WhateleyUniverse 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.
* The ''WebAnimation/RedVsBlue'' episode "Grey vs Grey" features this, with a DeliberateMonochrome 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. [[spoiler: The narrator reveals that the victim actually died of a heart attack before the shot was fired.]]

* 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 March 9, 1929, police were called to the residence of [[https://hubpages.com/politics/solving-the-locked-room-mystery 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".

Originally from crime fiction, Creator/JohnDicksonCarr being an acknowledged master. It is noteworthy that Creator/EdgarAllanPoe's short story ''Literature/TheMurdersInTheRueMorgue'', widely considered to be the first detective story, involves a Locked Room Mystery.

* ''Literature/{{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 episode.
* Although it is not a crime show, the anime ''Manga/{{Spiral}}'' has a number of locked room mysteries that the protagonist must solve, including one literal locked room murder.
* The ''Literature/HaruhiSuzumiya'' two-part episode "Remote Island Syndrome" (and the corresponding chapter in one of the light novels) has an example of this inside a locked room on an island hit by a terrible storm. [[spoiler:The murder turns out to be an act put forward by the people on the island to entertain Haruhi.]]
* ''Manga/CaseClosed'' frequently uses these, though it also plays with this trope, as Conan solves a case when he realizes that a man died [[spoiler: 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.
* ''Manga/TheKindaichiCaseFiles'' features one in majority of the stories.

* One of these came up in ''Manga/BlackButler''. [[spoiler: Turns out to be a prank by the Queen and Ciel playing Chessmaster to deal with a target of his]]
* ''Manga/Golgo13'', "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, [[BlatantLies 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. [[spoiler:"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.]]

* One of these pops up in ''Manga/FrankenFran'' 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. [[spoiler: The patients did it to themselves because they get off on Fran operating on them.]]
* In the ''Franchise/AceAttorney'' manga, "Turnabout Showtime" is referred to as "the world's smallest locked-room murder", when 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).

* The ''Literature/SwordArtOnline'' short story "Murder Case in the Area" is a form of locked room mystery involving players in an MMO where YourMindMakesItReal being [=PKed=] inside a town, where game mechanics make it impossible to be attacked or injured. [[spoiler: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 2003 ''Anime/AstroBoy'' show has an episode where 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. Turns out [[spoiler: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 the Detective Cilan episodes of ''Anime/PokemonTheSeriesBlackAndWhite''. 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 Herring}}s, 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 [[ChekhovsGunman 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.
* In ''Literature/RokkaBravesOfTheSixFlowers'', the main cast is within a forest when [[ClosedCircle 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.
* A multi-episode arc seen in ''{{Literature/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.

* ''ComicBook/DonaldDuck'' and especially ''ComicBook/MickeyMouse'' comics 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.

* ''ComicBook/AvengersInc:'' 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. [[spoiler:It helps if the killer can be smaller than the human eye, and if there's more than one of them.]]
* The central case in ''Comicbook/{{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.
* There's one featured in ''Franchise/{{Batman}}'' #700, where 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 [[spoiler:the present Carter Nichols went forward in time and killed his future self, causing his dead future self to return to the present. It's a [[TimeyWimeyBall bit confusing]].]]
* ''Recap/TintinKingOttokarsSceptre'' 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 Creator/AlanMoore's never-written DeconstructionCrossover, ''The Twilight Of The Superheroes''. Of course, it's easier to do in a world with superheroes, [[spoiler:including some who can turn invisible and intangible.]]
* ''ComicBook/IdentityCrisis2004'' began with the locked room mystery of Sue Dibny. It ultimately led to a lot of characters playing with the IdiotBall since they live in a world with numerous teleporters, time travelers, magic users, etc. Essentially, it's something that doesn't work in a superhero universe if the characters actually act in character.
* ''ComicBook/CableAndDeadpool'' 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 it's revealed [[spoiler: 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.]]
* In ''ComicBook/JonSableFreelance'' 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 NeverSuicide, and Jon turns detective to work out what really happened. [[spoiler:The victim had been given [[MedicationTampering 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.]]
* ''Comicbook/{{Grandville}}: Bete Noir'' has a man killed in his locked study while checking his "pneumail" (phonographic message cylinders sent by pneumatic tube). [[spoiler: 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.]]

* ''Film/BeauGeste:''
** 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 [[ElCidPloy 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. [[HowWeGotHere The climax reveals]] that [[spoiler: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 VikingFuneral and prevent him from being posthumously branded as a thief. After setting the fire, he then escaped over the opposite wall himself.]]
* Major plot point in ''Film/TheShawshankRedemption'', where [[spoiler:the protagonist 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.]]
* TheFilmOfTheBook for Creator/AgathaChristie's ''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.[[spoiler: 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.]]
* To some extent, ''Film/IRobot'' 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 BatmanGambit / ThanatosGambit on the part of the victim ''all at the same time.'' [[spoiler: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 BigBad's plot. Sonny was still in the room, in standby mode, when the police arrived.]]
* Inverted in ''Film/LawAbidingCitizen'', in that Clyde is somehow pulling off elaborate murders while locked in solitary confinement. [[spoiler:He had an escape tunnel.]]
* Teddy Daniels is brought to ''Literature/ShutterIsland'' to investigate a locked room mystery - in this case someone escaping from a locked and guarded room.

* Played with in ''Film/BloodSimple'', where the female lead [[BathroomBreakOut disappears from a bathroom]] without a trace.
* Plot point in ''Film/ThreeIron'' (Bin-Jip) where the hero uses [[MaybeMagicMaybeMundane some sort of stealth technique]] to fool the prison warden into believing he wasn't actually there in his cell.
* In ''Film/TheVerdict1946'' 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. [[spoiler: 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.]]

* In ''Film/TheCrimeDoctorsCourage'', Gordon Carson is found shot dead in a locked room with bars on the windows in what appears to be a case of suicide. [[NeverSuicide It isn't suicide.]]

* The original locked room mystery is "Literature/TheMurdersInTheRueMorgue", by Creator/EdgarAllanPoe. The story became the TropeCodifier 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 [[spoiler: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.]]
* Literature/SherlockHolmes had several locked room mysteries, including "Literature/TheAdventureOfTheSpeckledBand" ([[spoiler: the killer trained a venomous snake to get into the victim's room from an air vent]]), "Literature/TheAdventureOfTheEmptyHouse" ([[spoiler:The killer was a sniper with a specialized air gun]]), and ''Literature/TheSignOfTheFour''.
** 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.

** "Literature/TheatreOfCruelty": Parodied when Vimes's InternalMonologue brings up the complaint that "wizards made locked room mysteries commonplace" (though there are never any actual examples of this happening in the series).
** ''Literature/FeetOfClay'': The ultimately non-fatal poisoning of Lord Vetinari is a completely fair locked room mystery. It has an interesting twist that [[spoiler: the victim figures it out long before the "detective" does, but lets him do his job anyway.]]
** ''Literature/TheLastContinent'': A minor plotline involving the folk hero "Tinhead Ned" has him managing to mysteriously escape the prison. [[spoiler: 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]]

* Intentionally played to the point of absurdity in ''Literature/TheLongDarkTeaTimeOfTheSoul'' by Creator/DouglasAdams. 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.
* In Creator/JeffreyDeaver's novel ''Literature/TheVanishedMan'', 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.
* Played with in Creator/JasperFforde's ''Literature/TheBigOverEasy'', a detective story using nursery rhyme characters. "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.
* ''Literature/PragueFatale'': Bernie Gunther, a detective in UsefulNotes/NaziGermany, has to solve the case of a man who was shot to death in a locked room. Eventually he figures out that the man wasn't dead, he was only drugged. Bernie's boss UsefulNotes/ReinhardHeydrich pronounced the man dead, then pulled out a pistol and shot him after everyone else had left the room.
* Creator/JohnDicksonCarr, 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 Literature/DrGideonFell actually gives a lecture on the different ways a locked room mystery can be created. If the detective is Fell, Literature/SirHenryMerrivale, 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 (eg. [[spoiler: the victim was killed earlier and the body carried into the locked room by the person who claimed to have found it]]) through illusions ([[spoiler:eg. where there appeared to be two people, there was actually one person and a mirror]]) to technological/scientific tricks ([[spoiler:eg. 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.
* Randall Garrett used this trope often in his Literature/LordDarcy 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 being [[spoiler: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).]]
* "Literature/DeathInTheDawntime", by F. Gwynplaine Macintyre was written specially for ''Literature/TheMammothBookOfHistoricalDetectives'', and probably has the earliest setting ever for a detective story. It's a Sealed Cave mystery.
* ''Literature/TheMammothBookOfHistoricalWhodunnits'' opened with the AncientEgypt-set "Literature/TheLockedTombMystery" by Creator/ElizabethPeters, which is ExactlyWhatItSaysOnTheTin.
* The ''Literature/MillenniumSeries'' 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.
* Creator/ElleryQueen:
** ''Literature/{{The King Is Dead|1952}}''
** ''Literature/TheChineseOrangeMystery'': This locked room mystery 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 [[spoiler: presenting it as a locked room mystery would have actually given away the killer's identity immediately!]]

* Amelia Bones's body was found in this fashion by the {{Muggle}} police in ''Literature/HarryPotterAndTheHalfBloodPrince''. The police of course couldn't figure what happened, but the reader knew that she was a wizard killed by the Death Eaters.
* One of the "girls" disappears from a third-floor room in ''Literature/TheAlienist''.
* Creator/CDalyKing's ''Literature/ObelistsFlyHigh'' is a variant: the murder takes place on an airplane.
* The novel ''Literature/TheMysteryOfTheYellowRoom'', by Creator/GastonLeroux (better known as the author of ''Literature/ThePhantomOfTheOpera''), is a Locked Room Mystery that is also a perfect FairPlayWhodunnit. 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.
* One of the characters in the prologue to Creator/RogerLevy's ''Literature/RecklessSleep'' 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.
* The protagonist of the short story "Literature/TheManWhoReadJohnDicksonCarr" by Creator/WilliamBrittain murdered his wealthy uncle and escaped from the room through the chimney in order to confuse the inevitable investigation. [[SubvertedTrope It might have worked]] if he'd remembered to lock the door.
* The murder in Gilbert Adair's Creator/AgathaChristie pastiche ''The Act of Roger Murgatroid'' (whose title itself is a pun on Christie's ''Literature/TheMurderOfRogerAckroyd'') is of the locked room variety.
* In the first installment of the Max Liebermann Papers by Creator/FrankTallis, ''Literature/ADeathInVienna'', the murder is committed and discovered in an actual Locked Room scenario.
* One [[Literature/HeraldsOfValdemar Tarma and Kethry]] short story featured 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. [[spoiler: 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.]]
* Many of the ''Literature/SimonArk'' 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 [[ScoobyDooHoax much more mundane]].
* Rita Yarborough investigates one in the short story "Behind Locked and Bolted Door" in the collection ''[[Creator/JTEdson More J.T.'s Ladies]]''.
* In the light novel "Literature/AnotherNote" all five of [[IJustWantToBeYou 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 [[spoiler: to make a suicide look like a murder, effectively framing his death on himself]]. As Ryuzaki [[LampshadeHanging points out]], the mystery could be solved by assuming that the killer has a key to each room. Though that doesn't turn out to be the case; Ryuzaki had been [[spoiler: trying to lead the investigation astray]].

* The first book in the ''Literature/ObsidianAndBlood'' 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...

* Most of Literature/TheGreatMerlini's cases were some form of "impossible crime", with actual locked rooms common as well.
* ''Literature/TheNameOfTheRose''. The first death involves a defenestration beneath a window that cannot be opened, leaving the monks to suspect supernatural evil is at work. Brother William easily proves 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.
* A non-murder example in in Creator/FritzLeiber's sci-fi novel ''Literature/TheBigTime''; the trope is referred to practically by name, as chapter 9 is titled "A Locked Room" and includes a quote from the detective story ''Literature/ThePurloinedLetter''. 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.
* Author Creator/BaynardKendrick (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. [[spoiler: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.]]
* The ''Series/JonathanCreek'' 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: [[spoiler: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.]]
* ''Literature/BenSnow'': In "The Phantom Stallion", an invalid confined to a bed is murdered inside a room with the door latched and the window locked. [[spoiler: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 Mammoth Book of Locked Room Mysteries and Impossible Crimes'', is a mix of classics of the genre and new stories adding modern twists:
** "Literature/MurderInTheAir" by Creator/PeterTremayne (''Literature/SisterFidelma''), where a man is killed in an aeroplane toilet.
** "Literature/IceElation" by Creator/SusannaGregory, where a scientist disappears from a locked lab, in an EerieArcticResearchStation 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: [[spoiler: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.]]

* Perhaps unsurprisingly, Creator/AgathaChristie, as the one and only "Queen of Crime," ''loved'' this trope, although she was more likely to use it in short stories than full-length novels (likely because a single "impossible" mystery wasn't enough to sustain an entire two-hundred page book).
** In ''Literature/AndThenThereWereNone'' 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 [[TenLittleMurderVictims 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. [[spoiler: It turns out that the ''real'' killer [[NotQuiteDead faked their own murder]] to hide beneath suspicion, watched the final members of the household turn on each other and complete their work, then tided up after the victims and arranged their own suicide to correspond with the written records of how they supposedly died the first time.]]
** Several stories in ''Literature/TheThirteenProblems'' 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 [[RuleOfThree third]] moon has passed, and the titular blue geranium appears on the wall, suggesting that she had somehow been frightened to death. [[spoiler: 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. [[spoiler: 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 PhonyPsychic 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. [[spoiler: 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.]]
** In "The Dead Harlequin," a story in ''Literature/TheMysteriousMrQuin'', 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. [[spoiler: It turns out 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.]]
* Most of French mystery author Creator/PaulHalter's works fall into this category. For example in ''Literature/TheFourthDoor'' 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.
* In Creator/ElizabethPeters's "Literature/TheLockedTombMystery", 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.
* The trope is lampshaded in two ''Literature/KnownSpace'' 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. Creator/LarryNiven wrote the stories to show that you could use this trope in ScienceFiction.
* Creator/IsaacAsimov's "Literature/GimmicksThree": Using supernatural elements, the protagonist has found themselves locked into a perfectly cubical room, made from thick bronze. They are given the power to travel in any direction, and if they fail to escape before noon, they'll be a soul damned to eternal torment in {{hell}}. [[spoiler:The solution is to [[MoreThanThreeDimensions view time as a dimension]], and travel backwards.]]

* ''Literature/SherlockHolmesAndDoctorWasNot'': 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.
* ''Literature/FunJungle'':
** 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. [[spoiler: 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). [[spoiler: 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. [[spoiler: 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. [[spoiler:The culprit got in through a Prohibition-era secret passage.]]
* ''Literature/ForestKingdom'': 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.
* ''Creator/GKChesterton'' used several different variants of this trope in various of his mystery novels.
** ''Literature/FatherBrown'':
** ''The Secret Garden'' has an inverted variant, where the murder victim somehow got ''in'' to an enclosed garden without anyone noticing. [[spoiler: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. [[spoiler: 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 summerhouse]].
** ''Literature/ThePoetAndTheLunatics'': "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.
* ''Literature/IrishVillageMysteries'': ''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. [[spoiler: 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.]]
* ''Literature/JaineAustenMysteries'': 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 [[spoiler:that she was escaping via a hole in the wall hidden from sight by Jaine's bed.]]
* ''Literature/{{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, and 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). [[spoiler: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 Room in the Dragon Volant" by Creator/JosephSheridanLeFanu: 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 [[spoiler:was targeted by con men who induced him to leave his room by way of a secret passage, and then murdered him.]]
* ''Literature/EncyclopediaBrown'' 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.[[spoiler: 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.]]
* In Christianna Brand's "The Gemminy Crickets Case" Giles [[MuggedForDisguise 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.
* ''Literature/TheNakedSun'' 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. [[spoiler:She ''is'', however, [[FoundTheKillerLostTheMurderer 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.]]

* An interesting [[InvertedTrope inversion of this trope]] occurs in ''VideoGame/TheElderScrollsIVOblivion'' 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; [[spoiler: 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 [[spoiler: there's no gold, either. Well, not for them, anyway.]]
** Unfortunately, it's programmed so badly that [[spoiler: 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. [[spoiler:[[PortalPicture Turns out, he's still in the room]].]]
* ''VideoGame/DiscoElysium'' 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 evey plausible angle he could think of, and a few implausable angles too. Eventually, he passes it on to the second detective, [[spoiler: a pre amnesiac you,]] who solves it in under an hour. [[spoiler: 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.]]
* ''VideoGame/TraumaTeam'''s Forensics mode features a stage with this trope's exact name.
* Dr. Schrader's [[DisneyDeath death]] in ''VideoGame/ProfessorLayton and the Diabolical Box'' is one of these. Layton concludes that [[spoiler: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]].
* In one chapter of ''VideoGame/GhostTrick'', 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. [[spoiler:She activated a RubeGoldbergDevice murder machine, which was designed to kill anyone who turned on the lights and then destroy any evidence of its own existence.]]
* The ''VideoGame/StarTrekOnline'' 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. [[spoiler: 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.]]
* In ''VideoGame/DragonAgeInquisition'', 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. [[spoiler: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 Mermaid's Tongue'' also centers around one, with a submarine captain alone in a locked room save for a recently-opened ancient stone cauldron.

* In the first ''[[VideoGame/PaperMario64 Paper Mario]]'' game, 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. [[spoiler: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.]]

* The case that ''VideoGame/TangleTower'' 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 mysteries on ''Series/{{Banacek}}'' were all 'impossible crime' thefts, including locked room mysteries.

* ''Series/{{Andromeda}}'': Tyr is alone with President Lee of Castalia to apologize to him for insulting him during a state dinner, when everyone hears Lee yelling, then two shots from a force lance, and rush back in to find Lee dead and Tyr unconscious. Tyr is the obvious suspect, but insists he's innocent--in large part on the grounds that [[VaryingCompetencyAlibi if he'd wanted to kill Lee, he wouldn't done it in a way that so obviously pointed the finger at him]].

%%** And his successor D.I. Humphrey Goodman solves one of these in the final episode of series 3. ZCE

* A more diluted form sometimes appears in ''Series/{{CSI}}'' where the puzzle is eventually unraveled by an eccentric protagonist using more obvious clues and AppliedPhlebotinum.
** One episode involved a murder committed where all the doors and windows were locked securely from the inside. [[spoiler: The killer was a cable installer who unlocked a window to a hidden attic while working in the house.]]
* In ''Series/TheXFiles'', the puzzle is typically subverted when an eccentric protagonist (AgentMulder), on the basis of flimsy evidence and wild speculation, reveals that a MonsterOfTheWeek did it. In this case, the monster is the one using AppliedPhlebotinum in the form of special monster powers. Two episodes in Season 1, "[[Recap/TheXFilesS01E03Squeeze Squeeze]]" and "[[Recap/TheXFilesS01E21Tooms Tooms]]", epitomize this trope variant, with the monster managing to get at his victims in otherwise inaccessible places through his mutant ability to [[RubberMan squeeze through]] tiny vents, windows, chimneys, et cetera.

* One ''Series/CrossingJordan'' episode involved 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. [[spoiler: It turned out to be self-inflicted.]]
* On ''Series/KamenRiderAgito'', 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.''
* ''Franchise/StarTrek'':
** A classic example is the ''Series/StarTrekTheOriginalSeries'' 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. [[spoiler: Eventually, the computer aboard ''The Enterprise'' discovers the truth, that "Redjac" is an incorporeal being that [[EmotionEater feeds on fear]] which has been behind several unsolved cases of serial killers on many worlds, including UsefulNotes/JackTheRipper.]]
** ''Series/StarTrekDeepSpaceNine'':
*** Season one's [[Recap/StarTrekDeepSpaceNineS01E04AManAlone "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. [[spoiler:It turns out that the "victim" is actually the killer, and the body found is that of a clone.]]
*** In season seven's [[Recap/StarTrekDeepSpaceNineS07E13FieldOfFire "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. [[spoiler:LTJG. Ilario was shot using a firearm that had been combined with a [[{{Teleportation}} transporter]] that ''beamed'' its bullet to its target.]]
* The mysteries on ''Series/{{Banacek}}'' were all 'impossible crime' thefts, including locked room mysteries.

* The first murder in ''Literature/LessonsForAPerfectDetectiveStory'' 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 [[spoiler: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.]]
* ''Series/ElleryQueen'': 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.
* ''Series/{{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. The answer to the mystery [[spoiler: eludes everyone, including Sherlock.]]
** Sherlock realizes at the end how the murder was committed: [[spoiler: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.]]
* ''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. [[spoiler: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. [[spoiler: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.]]
* The Sixties revival of ''Series/{{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. Turns out [[spoiler: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 ''Series/{{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. [[spoiler: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.]]

* ''Series/TheDoctorBlakeMysteries'': In "Room Without a View", the BodyOfTheWeek is found asphyxiated in a hotel room that has a chair jammed under the door handle.
* ''Series/FatherBrown'':
** In "The Curse of Amenhotep", the VictimOfTheWeek is found alone in a room that was locked from the inside. It turns out that [[spoiler: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 VictimOfTheWeek 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 VictimOfTheWeek 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.

* ''Series/TheCoroner'': In "Napoleon's Violin", the VictimOfTheWeek is stabbed to death inside a locked room.
* The ''Series/{{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 [[IfIWantedYouDead had he intended to kill the President]], [[MakeItLookLikeAnAccident 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. [[spoiler:It turns out Tyr's weapon had been reprogrammed by the real killer to fire {{Homing Projectile}}s remotely, and Tyr was electrocuted by a failsafe system to prevent unauthorized use (the killer having overwritten Tyr's owner registration).]]
* ''Series/ColonelMarchOfScotlandYard'': 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.

* Literature/SherlockHolmes had several locked room mysteries, including "Literature/TheAdventureOfTheSpeckledBand", "Literature/TheAdventureOfTheEmptyHouse", and ''Literature/TheSignOfTheFour''.

* ''ComicBook/IdentityCrisis'' began with the locked room mystery of Sue Dibny. It ultimately led to a lot of characters playing with the IdiotBall since they live in a world with numerous teleporters, time travelers, magic users, etc. Essentially, it's something that doesn't work in a superhero universe if the characters actually act in character.

* In Christianna Brand's "The Geminney Crickets Case" Giles [[MuggedForDisguise 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.