'Locked-Room' Mysteries and Other Impossible Crimes
A popular sub-genre in mystery fiction, especially during the Golden Age of the 1920s and 1930s, is the so-called locked-room murder, which can be defined as any crime committed in such a way that it seems to be impossible to determine how it was done. John Dickson Carr was the master of this class of detective story
This is the detective story in its most ‘intellectual’ form (along with the unbreakable alibi and the least likely suspect), a challenge by the author to the reader, and is therefore a matter of taste, especially for readers who prefer suspense or fast action or literary critics who insist that character traits are more important than ratiocination. That should not imply that the locked-room murder, if well done, lacks these elements.
Many readers prefer their locked-room murders in short-story format as it is difficult to sustain momentum in a novel when the puzzle is the main point. There is also a much larger selection among short stories. Carr was exceptional in his ability to combine a good impossible crime with a compelling plot and interesting characters, but it will surprise many readers to know that few of his many detective novels are actually locked-room murders (most of his plots involved misdirection of another sort); he far more excercised this allo in the short-story form. However, short stories are beyond the range of this brief essay, as there are so many of them. Mystery aficionados should look to the specialist collections, such as Robert Adey and Douglas Greene’s Death Locked In (1987), The Mammoth Book of Locked-Room Murders and Impossible Crimes (2000), and others. There is also Hans Stefan Santesson’s Locked Room Reader (1968), long out of print but one of the first and best of its type. See also Adey’s definitive bibliography Locked Room Murders and Other Impossible Crimes (1979) – if you can find it and afford it
Rooms locked from the inside (or under constant observation)
Earliest is Poe's classic Murders in the Rue Morgue; there is also a locked-room murder in LeFanu's Uncle Silas where he reused material from earlier stories); both solutions involve hocussing of windows. This sort of thing is now seen as rather primitive, but JDC used it successfully in The Cavalier's Cup, Till Death Do Us Part, and in a few other cases. Fiddling with bolts or locks from outside the door with keys left inside is also rather dated, but that doesn't mean Carr never used that trick convincingly (e.g., The Dead Man's Knock). A couple of ingenious key-manipulation locked-room mysteries are Ellery Queen's Chinese Orange Mystery and Edgar Wallace's Clue of the New Pin. An unusual variation is the classic 'locked-chest' murder: Smallbone Deceased, by Michael Gilbert, or see also Edmund Crispin's Holy Disorders, which is a 'locked-cathedral' murder. Israel Zangwill's Big Bow Mystery (1895) is one of the first locked-room novels that really 'works' and used the 'impossibility' as a critical plot element, not just a diversion.
Carr's own favorite impossible crime story was Leroux's Mystery of the Yellow Room (1908). The plot is ingenious, but in fact the book is pretty awful (the detective Rouletabille is absurd) and falls under the generally French category of Grand Guignol. The impossibility involves witnesses observing the only doorway the murderer could have used, and of course no one was seen entering; Carr used this device in It Walks by Night and (a variation of the theme, where the murderer is seen entering the room but vanishes from it) in The Three Coffins, to cite just two examples.
Secret Passages and Hidden Traps
Secret entrances or other hidden accesses (usually considered cheating in this category) were rarely used by Carr, but when he did (The Judas Window), he surpassed himself. (But not very successfully in Death-Watch.) Booby-trap stories are mostly unconvincing because too much of the success of the device depends on pure luck (most writers who used these ploys never considered Murphy's Law that if anything can go wrong it will). The classic original was Wilkie Collins's "Tale of a Terribly Strange Bed." Carr tried some, but succeeded reasonably only with a couple of them: The Reader Is Warned and Fatal Descent (collaboration with John Rhode); it is very unconvincing in a book like The Man Who Could Not Shudder, involving a flying gun. Edmund Crispin's Swan Song, like Fatal Descent, varies from the tradition sealed room by being set in an elevator; in both cases, one shudders to think what could have gone wrong and sent the kil straight to jail without passing Go. (My all-time favorite absurdity is Van Dine's Scarab Murder Case, where the murderer tilts up an Egyptian statue on top of a library shelf with a pencil stub knowing that his victim's compulsive tidiness will lead him to try to straighten it, with the result that it will fall on his head.)
In many cases (especially with Clayton Rawson's Great Merlini stories and Joseph Commings tales about Senator Brooks Banner), the impossible crime situation is created by use of professional magic -- mirrors, misdirection, and the like. One trouble with this approach is that it is rarely convincing (as are explanations about floating ladies, etc. -- the trick works but you still wonder how you could be fooled); also, these stories do not stand up well to re-reading, since everything depends on the gimmick and other aspects of plotting such as characterization and motivation tend to be overlooked. Opportunity is all. There is not much to be said about this form of locked-room murder, as there are very few examples. But once again, The Three Coffins has to be mentioned
'No Footprints in the Snow'
Another type of impossible crime is the 'killer left no footprints' situation -- where the victim is found stabbed or strangled in a place where access by the murderer had to have left traces: a field of snow, a beach of wet sand, a stretch of mud, etc. Carr used this a lot (Witch of the Low Tide, White Priory Murders, Problem of the Wire Cage, and so on). Another book in this category, which Carr described as a classic but which apart from its ingenuity and spooky north-woods setting is not that good (because the characters, such as they are, behave irrationally and inconsistently), is Hake Talbot's Rim of the Pit. It has risible scenes involving something like pole-vaulting and the near frightening to death of somebody by having him flee from a wendigo by attaching a halloween kite to his back! All in all, however, the no-footprints puzzle provides one of the best impossible crime situations
The Impossible Suspect
You (and the detective) know or suspect who the murderer is, but all indications are that he couldn't have done it anyway, or he has an apparently unassailable alibi. Carr handled this well in To Wake the Dead or Hag's Nook, for example. Rex Stout's League of Frightened Men is a classic of this sort. The hidden serial killer (a pillar of the community) is a subset of this category (Carter Dickson's My Late Wives, Night at the Mocking Widow, etc.). One of the best multiple-murder mysteries is Ellery Queen's Cat of Many Tails; Agatha Christie did a several good ones as well (esp. The Pale Horse, And Then There Were None, and The ABC Murders). S. S. Van Dine (always a good example of how to overdo it) had the Greene and Bishop Murder Cases; the killer is easy to spot because he/she is practically the only person left in the cast by the time the book nears the end (the Tontine approach to detection). A major aspect of this sort of plot is misdirection of the sort G. K. Chesterton specialized in -- that is, natural assumptions based on the reader's preconeptions, and abetted by the author's narrative slant, lead one to ignore what seems obvious in retrospect
The final category to be mentioned here is the Grand Rigmarole, where the impossible situations, bizarre events, and wild characters are piled one on top of the other, and the story never stops moving, twisting, and turning. Try The Arabian Nights Murder or The Blind Barber, among Carr's works, or Dickson's Punch and Judy Murders. The Devil in Velvet, one of Carr's historical fantasies, has most of everything you could ever want in it, including impossibilities and even Satan himself; masterpiece! Fire, Burn! and The Burning Court also weave in the supernatural/science fiction very successfully. Michael Innes did some fine ones (not really 'impossible crimes'), such as Hamlet, Revenge!, What Happened at Hazelwood, and Appleby on Ararat (unreal!). Phantasmagorical classics include: several Ellery Queens (e.g., And on the Eighth Day, House of Brass); JDC's Lost Gallows; McCabe's Face on the Cutting-Room Floor; Crispin's The Moving Toyshop; Innes's Lament for a Maker. This requires a lot of imagination, even when the writing is terrible as with McCabe, and the works of Harry Steven Keeler. ----