Two coffins of the way through The Three Coffins(aka The Hollow Man) the author, John Dickson Carr, breaks into the narrative through the words of his serial detective Dr Gideon Fell. Fell responds to a question:
“Because … we’re in a detective story, and we don’t fool the reader by pretending we’re not. Let’s not invent elaborate excuses to drag in a discussion of detective stories.”
He then let’s the reader know what counts as contravening his/her rights regarding the possibilities in solving a locked-room mystery:
“the low … trick of having a secret passage … so puts a story beyond the pale that a self-respecting author scarcely needs even to mention that there is no such thing. We don’t need to discuss minor variations of this outrage: the panel which is only large enough to admit a hand; or the plugged hole in the ceiling through which a knife is dropped, the plug replaced undetectably, and the floor of the attic above sprayed with dust so that no one seems to have walked there.”
Then proposes a taxonomy of locked-room solutions. First where there was no murderer in the room:
1. It is not murder, but a series of coincidences ending in an accident which looks like murder. eg a crack on the head from a piece of furniture. “the most popular object is an iron fender”
2. It is murder, but the victim is impelled to kill himself. Gas, poison, induced hysteria.
3. It is murder, by a mechanical device. Mechanical trap, concealed guns, hidden poisoned needles, “Even” says Fell ” a glove is electrified”. Er, ok.
4. It is suicide made to look like murder. Often the suicide weapon is made to vanish – as with stabbing with icicle or a gun whipped out of sight mechanically
5. It is murder, but the victim is already dead. Illusion and impersonation are used. eg, the murderer impersonates the victim going into the room, and comes back out again as himself, etc
6. It is murder, committed outside the room that appears to have been committed inside via remote, ‘long distance’, or constricted access (thin blade through a hole).
(He then includes leaving poisonous snakes and scorpions in the room as part of #6, though I would class that under an expanded point 3 of ‘living devices’, where the vanishing is caused by scuttling off.)
7. It is murder, but, as the converse of 5, the victim is not yet dead. Usually incapacitated, or apparently dead, the murder is committed by subterfuge and/or misdirection after the room is breached by the witnesses.
He then moves on to cases where the murderer was in the room, and the means of making the room seem locked from the inside, which i won’t recount. I am not going to spoil the book, which is superb in every way you may want and a MUST READ, but the mysteries at hand in the book are NOT COVERED in the ontology. Which is sort of unfair I thought given the context of the chapter.
Even though there is this sleight of hand, the great thing about these sort of mysteries, as anyone watching Jonathan Creek will atest, is that you can sometimes intuit the ‘trick’ and whodunnit, because it has to be the least likely of all suspects — it is like when you start to understand how the mind of a particular crossword setter works. My own guess turned out to be well within the purlieus of truth, though i was nowhere near working out the ‘how’, which was ingenious to say the least. And I didn’t quite follow all the shenanigans with the main illusion involved. When the FT book club have all read it, someone plz expln.