‘She smiled back at me, closed my door, and a few moments later I heard her key turn in the lock.’ ‘Indeed,’ said Holmes, ‘Was it always your custom to lock yourselves in at night?’
The locked room mystery has been a staple of detective fiction since Edgar Allan Poe’s The Murders in the Rue Morgue presented Auguste Dupin with two corpses and apparently no way for the murderer to have entered or left. Admittedly Poe “cheated” rather in this case – the skylight had a spring catch which allowed it to shut and lock itself – but the basic situation has been repeated frequently over the years, particularly as a feature of the “clue-puzzle” whodunnit, being used as a plot device in stories featuring Sherlock Holmes (The Adventure of the Speckled Band), The Thinking Machine (The Problem of Cell 13) and Miss Marple (The Blue Geranium), amongst others.
The locked room has an obvious appeal for fans of detective fiction. It immediately presents the reader with a problem: something apparently impossible has happened, and since whodunnits do not countenance the inexplicable or the supernatural, there must be a solution. Like a hermetically sealed test-tube, it is a microcosm of the mystery genre: a puzzle, a crime, a victim, a solution, and all bracketed within one room – which is probably the reason it has been used in so many short stories.
It is a microcosm in another way: all classic detective fiction tends towards this enclosed space. Agatha Christie, in particular, seem to specialise in ingenious ways of cutting off her characters from the outside world, whether in a train (Murder on the Orient Express), an aeroplane (Death in the Clouds), a pleasure-boat (Death on the Nile) a private island (And Then There Were None) or just the old traditional house-in-a-storm-when-the-telephone-lines-are-down (The Mousetrap). This has the obvious result of increasing suspense, especially in the stories where the murderer continues picking off the other suspects one by one. (This variant always seems to borrow the logic of medieval witch-tests – I wonder if it was Colonel Ban…whoops, no, turns out he’s innocent. Disembowelled, but innocent.) There is a more basic narrative need at work, though – more basic even than the growing tension. The locked room (or train, attic, apartment block, caravan…) sets limits to the mystery. A murder which occurred sometime between Tuesday and Friday in the rough area of Kings Cross would be very tricky material for a detective story: the classic whodunnit depends upon specific times and places, measured distances, cross-checked timetables, the exact quantity of ash which falls from a cigar in a quarter of an hour. As a genre, it insists that the world makes sense, and can be analysed logically. The limiting of time and space goes some way towards reducing the messy, complicated issue of murder to a crossword puzzle, or a theorem. When this has been achieved, it can be solved.
This drive to analyse is more than a requirement of the whodunnit genre, it is an emotional need implicit in all novels. Novels allow the awkward, graceless stream of details which make up our lives to be frozen, set down and arranged in patterns which make them meaningful. The conventions of “beginning, middle and end”, or “conflict, turning-point, resolution” impose formal patterns on their material which are similar, though subtler, to the rhymes of poetry or the verse and chorus of a song. In fact, the whodunnit seems rather like much of modern poetry in its insistence upon the importance of mundane items and events. Where William Carlos Williams draws attention to the wonder and significance of wheelbarrows and ice-boxes (in his own phrase, “so much depends” upon them), authors like Agatha Christie and Arthur Conan Doyle make them turning-points between life and death, guilt and innocence, investing cups of cocoa, walks in the garden or train tickets with the power of sacred items.
However, the comparison with crosswords and poetry shouldn’t imply that the conventions of the detective story merely provide an orderly or aesthetic satisfaction. They’re a popular, disposal form, but they deal with the same themes which have motivated the great tragedies: death, guilt, and the search for meaning. (It is worth bearing in mind that Agatha Christie was an archaeologist, Arthur Conan Doyle experimented with spiritualism, and Dorothy L. Sayers translated Dante’s Inferno.) They try to make sense of human experience through the social conventions of English middle-class life and train timetables, but they are articulating the same need for explanation that makes the bereaved relatives ask the minister “Why?” In sermons and newspapers, the anguish of a young person’s death is often described as “a terrible waste”, as if Newtonian physics could be applied to the mysteries of life and death. Agatha Christie’s novels, with their fussy and sometimes tedious emphasis on the details of alibis, attempt to do just that, to call death to account and make the world obey a meaningful economy.
This is why, according to the classic “rules” of the form, the writer is obliged to show the reader all the significant clues, and not to introduce some completely extraneous solution at the end of the mystery. The inconsistency in an alibi, the missing half an hour, the knowledge that a suspect should not have had, must be presented to the reader, but swamped by the mass of details and “red herrings” so that their significance is not immediately apparent. Whodunnits are often read as an implicit challenge to the reader, to match their wits against the mystery, though personally I have practically never “solved” one except by a lucky guess or the unfair application of the “least-likely person” convention. I don’t know how far mystery writers intended their works to be solvable, and how many readers would bother to sit up all night smoking and thinking the problem out, rather than spend the same time reading the book, but the denouement ideally shows that the solution came out of the clues presented – back to the analogy with an equation. On this level at least, the more baffling the collection of clues, and the more tightly they are bound into the solution, the more satisfying we find a whodunnit, which suggests that such self-sufficiency is an essential element of the literary job it has to do. It presents a completely incomprehensible jumble of facts and objects, then explains them into a meaningful pattern. Most importantly, we see the investigation occurring – unlike lyric poetry, which offers a transcendent moment of explanation, the whodunnit shows us the process by which understanding is reached, even if we only understand them fully in retrospect, when the sleuth reveals what he was up to with the dates on the tulip crate.
Of course this explanation, or “movement from disorder to order”, doesn’t happen in an orderly straight line. The sudden “dénouement” has less in common with the solving of a crossword than the flourish with which a conjuror pulls off a trick. In fact, considering the importance of a magician’s props, the art of misdirection, the characteristic patter which conceals vital sleights of hand, the analogy seems to get stronger, and the locked room looks more like the heavily padlocked box into which the spangly assistant steps before being cut in half, stabbed by swords, or disappearing entirely. Whodunnits are a crowd-pleasing art as well as a philosophical problem, and people have always been interested in entertaining feats which “defy death”. There is a Houdini-style bravado in an author taking a body, putting it in a bedroom, changing the locks, hiding one key under the jewel case, hanging the only other duplicate in full view in the hall, brewing strong coffee to stop the maid outside the door from falling asleep, boarding over the window (with rusty nails) and throwing the digitalis pills into the shrubbery, challenging the reader to speculate how they will “get out of this one”. Though conjurers don’t reveal the method behind their tricks, they also produce apparently impossible effects, which are comfortingly underwritten by the knowledge that there is a logical explanation.
Magicians perform their illusions in front of large audiences, however – in the whodunnit we are more often presented with the image of the detective sitting alone thinking. The enclosing effect I mentioned at the beginning seems to apply to solving crimes as well as committing them. Though Sherlock Homes did on occasion dash over the Yorkshire moors, or shadow a suspect in disguise, the image which persists is him immobile in his chair, declaring “it is quite a three pipe problem.” Poirot certainly casts scorn on Inspector Japp’s eagerness to dash here and there, rather than composing himself and applying “the method” and “the little grey cells.” Some carry this to extremes: Nero Wolfe refuses to leave his house, solving cases from the reports which are brought to him, but all the classic detectives tend to mirror the locked room in their own methods of deliberation – just as the novel locks their thoughts away from us, only allowing us access via the muddled and misdirected sidekick. This silent deliberation is mirrored once more in the form, by the reader themselves. Holmes, solitary in his pipe smoke and armchair, Poirot sitting at a desk, Miss Marple in her easy chair, looking casually out at the garden, all look curiously like a reader, who cuts themselves off from the real world to concentrate on the internal world of the book, only discussing it after the experience is over. Paradoxically, despite the special talents of these sleuths, their arm-chair self-sufficiency reassures us that mysteries can be resolved through the quiet, analytical action we are undertaking as we read. The whodunnit, secure within its “binding”, allows some of the most difficult questions of human experience to be contained, broken down and resolved in the space of a few hours and a few hundred pages. Whether they stay resolved is another matter – and possibly the key to the genre’s addictive tendencies!