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The locked room mystery is a sub-genre of detective fiction wherein a murder or other crime is apparently committed under impossible circumstances: no one could have entered or left the scene of the crime, and the death involved could not have been a suicide. Such stories normally follow other conventions of classic detective fiction, in that the reader is presented with the puzzle and all of the clues, and so encouraged to solve it before the solution is revealed in a dramatic dénouement.
The following are examples of "impossible" or "locked-room" crimes:
The victim is seen walking alone in the middle of a snow-covered street. A voice is heard to threaten him, and a shot rings out. An examination of his body shows the shot was fired from close range, but no killer is to be seen and no other footprints are found on the scene. The Hollow Man (U.S. title: The Three Coffins), a novel by John Dickson Carr)
A man is found with his throat cut on a rock in the middle of a footprint-free stretch of sand wet from the receding tide. The crime is so recent that the victim's blood has not yet clotted, yet the occupants of a fishing boat less than 100 yards away swear they saw nobody approach the rock for hours. (Have His Carcase. a novel by Dorothy L. Sayers)
A man is seen by several witnesses committing a crime, and is found dead later. Examination of the body indicates he was already dead before the crime was committed. (The Amorous Corpse, a short story by Peter Lovesey;Captain Leopold and the Ghost-Killer, a short story by Edward D. Hoch)
A man dies in a room at the top of a tower in a Scottish castle that is believed to be haunted, where people have committed suicide in rapid succession. Despite evidence showing the people had no reason to kill themselves, they are shown to have been alone at the time of the murder. (The Case of the Constant Suicides, a novel by John Dickson Carr)
A man is shot in a guarded room, and the still-smoking gun was delivered next door in a sealed envelope some time previously. (The X Street Murders, a short story by Joseph Commings}
The murderer is seen entering a room by a witness, but when the room
is opened only the corpse of the victim is to be found. (The Hollow Man)
A man volunteers to spend the night in an attic room reputedly haunted
by the spirit of a woman previously stabbed to death there in impossible
circumstances. The door is sealed. When the seals are broken, a complete
stranger lies there dead from stab wounds and the other man has vanished.
(La Quatrieme Porte)
A man is found dead, and his wife dying, in a room locked from the inside. She had been able to call for help after shots were heard. There is no gun in the room and a search reveals no other person present. (Six Crimes Sans Assassin)
A woman is found dead in a room with her ex-husband, with the gun that killed her in his hand. Although the gun is proven to have killed her, her ex-husband is a detective whom the reader has grown to trust over a long series of short stories featuring him as the explainer of locked room mysteries. (The Leopold Locked Room, a short story by Edward D. Hoch)
A man is stabbed to death in a summer house to which every access route is guarded and in which no weapon is to be found. (The Oracle of the Dog, a short story by G.K. Chesterton)
A horse and buggy vanish in a covered bridge. Their tracks can be seen going in to the bridge, but none come out on the other side. (The Problem of the Covered Bridge, a short story by Edward D. Hoch)
The audience is allowed to inspect the magician’s cabinet from all sides before he steps inside to perform his vanishing trick and the curtain descends. When the curtain goes up again, the magician is still in the cabinet – strangled. (Death by Black Magic, a short story by Joseph Commings)
The drunken brother of a billionaire industrialist fires an empty gun in the direction of his brother, who is some distance away sealed inside a safe-room. At that precise moment, the industrialist is shot, and no gun can be found in the sealed and guarded room. (The King is Dead, a novel by Ellery Queen.)
Two people are found shot to death at point-blank range inside a room locked on the inside. No gun is found in the room, and no bullets are found in either body. See the True Crime section.
True (real life) "locked-room" crimes :
“Truth, I may remind you, is stranger than fiction.” - Henri
Bencolin The Lost Gallows
Alfred Russel Wallace described events occurring in the Baltic in 1844 thus: “During the disturbances at the Cemetery of Ahrensburg in the island of Oesel, where coffins were overturned in locked vaults, and the case was investigated by an official commission, the horses of country people visiting the cemetery were often so alarmed and excited that they became covered with sweat and foam. Sometimes they threw themselves on the ground where they struggled in apparent agony, and, notwithstanding the immediate resort to remedial measures, several died within a day or two. In this case, as in so many others, although the commission made a most rigid investigation and applied the strictest tests, no natural cause for the disturbances was ever discovered.”
George Colvocoresses, captain of the USS Saratoga during the American Civil War was, according to his biography, mysteriously murdered in Bridgeport, Connecticut on June 3, 1872 while on his way to New York. According to his great-great-grand-daughter, however, his insurers later alleged that his death was a suicide, as the bullet wound he suffered was conveyed at close range through his heart, without the bullet penetrating his outer garments. It remains unexplained why, if this were the case, he would choose the busiest time of day on a busy street, nor why his shirt remained tucked in his trousers after death.
Herr Konrad was a merchant in Berlin in the 1880’s. His wife and five children were found dead in their cellar. The ponderous cellar door had no keyhole or any space around the molding, and was securely bolted on the inside. There was not the slightest aperture anywhere and the door fitted so tightly around the frame that a piece of paper could not have been passed through any crevice. However, the examining magistrate, using a powerful lens, eventually found a barely discernible hole just above the bolt on the inside of the door. There was no corresponding hole on the outside, but he found a small spot where the paint seemed fresher. Inserting a heated hatpin through the hole on the inside, he pushed out a hole in the exact centre of the painted spot. A piece of horsehair and a slight film of wax were found attached to the hatpin.
Konrad had bored a tiny hole through the door above the bolt, looped a piece of horsehair over the bolt's knob, and slipped the two ends through the hole. By pulling upwards on the bolt-knob until the horsehair loop was disengaged, he was able to withdraw the horsehair through the hole, which he then filled up with wax and painted over. Konrad was executed; it was said he got the idea from a mystery novel. (K. Bernstein, "Der Merkwürdige Fall Konrad.") The murderer in Edgar Wallace's The Clue of the New Pin uses Konrad's technique.
In 1898, Elisabeth, Empress of Austria-Hungary, was on the quay at Lake Geneva awaiting the steam ferry to Montreux when, without warning or apparent motive, the anarchist Luigi Lucheni plunged a needle file into her heart. Because of the very thin nature of the wound, the Empress did not realise that she had been fatally injured and walked unaided to her cabin, where she collapsed and soon died. It is not known whether she locked the cabin door behind her -- which would have created the appearance of a locked room murder. At least one prominent French locked room expert, Roland Lacourbe, believes that this notorious event was the inspiration for Gaston Leroux's The Mystery of the Yellow Room and it also bears an unmistakable resemblance to the central crime in Maurice Leblanc's Therese and Germaine. In Georgette Heyer's Envious Casca, the villain took his inspiration directly from an account of Empress Elizabeth's death.
According to a report in the The New York Times, March 10 and 11, 1929, Isidore Fink, of 4 East 132nd Street, New York City, was in his Fifth Avenue Laundry on the night of March 9, 1929 with the windows closed and door of the room bolted. A neighbor heard screams and the sound of blows (but no shots) and called the police who were unable to get in. A young boy was lifted through the transom and was able to unbolt the door. On the floor lay Fink with two bullet wounds in his chest and one in his left wrist, which was powder-marked. He was dead. There was money in his pockets, and the cash register had not been touched. No weapon was found. The man had died instantly, or almost instantly.
There was a theory that the murderer had crawled through the transom. But to do so he would have had to be no bigger than a small boy and would have had to leave the same way, as the door was bolted. Another theory had the murderer firing through the transom, but Fink's wrist was powder-burned, indicating that he had not been fired at from a distance. More than two years later, Police Commissioner Mulrooney, in a radio-talk, called this murder, in a closed room, an "insoluble mystery." The crime was said to have inspired William March’s “The Bird House” and Ben Hecht’s “The Mystery of the Fabulous Laundryman.”
On the 16th of May 1937, Laetitia Toureaux was found stabbed to death in an otherwise empty 1st class compartment of the Paris Metro. The subway train had left the terminus, Porte de Charenton, at 6:27 p.m. and had arrived at the next station, Porte Dorée, at 6:28 p.m. Witnesses at both stations swore nobody was seen getting in or out of the compartment, and witnesses in both adjacent compartments swore that nobody had tried to enter the one where Mlle. Toureaux's body was found. The murderer had one minute and twenty seconds at his disposal. Neither the method nor the murderer was ever discovered.
In 1979, Morton Conroy, a well-known Long Island barbecue manufacturer and his wife were found shot to death at point-blank range inside a room locked on the inside. Not only was no gun found in the room, but no bullets were found in either body.
It transpired that a maid who had been hired several months earlier had a brother who had died a slow and agonizing death following the explosion of a Conroy barbecue. She had taken her revenge and staged the locked-room to challenge the police, who quickly discovered the special tweezers she had used to lock the door after removing the gun from the room. The disappearance of the bullets was a far more ingenious effort, however. She had fabricated the bullets from pieces of meat and bone, honing the bone into a bullet shape and packing it and the attached meat into a shell case. At point-blank range, the bone pierced the victim's heart and shattered into tiny pieces, and the meat was dispersed into the surrounding flesh where it became practically invisible. The technique was later used in a fictional locked-room mystery published in the UK and the US, as well as in an episode of CSI: Crime Scene Investigation.
In 1996, the body of Chicago mystery writer Eugene Izzi, wearing a bullet-proof vest, was found hanging outside the window of his 14th-floor office above Chicago's Loop[1]. The rope slip-knotted around the corpse's neck passed back through the window, and was tied to the leg of a desk. On the floor was a loaded revolver. A hole, as if from a struggle, was bashed in one plasterboard office wall, but the office was locked from the inside.
A baffling murder? Or an elaborate, self-mocking suicide, with the locked-room angle thrown in to ensure prime-time coverage? Or could Izzi, a writer known to be fanatical about research, have been trying to find out how it felt to dangle by the neck outside an office window? In his pockets, besides a can of Mace, several hundred dollars in cash and a set of brass knuckles, were three computer disks. It has been reported that although the disks don't add up to a book and are unlikely to be published, they describe a scene almost exactly like that of the author's death--right down to the pistol and the holed wall--in which white racist militia members hang a detective-story writer outside his office window.
A similar series, Kindaichi Case Files, features a locked room mystery in almost every story. Many of these are original, ingenious and meticulously explained; early examples are The Opera House Murders, Death TV and Smoke and Mirrors.
http://www.answers.com/topic/locked-room-mystery