I hope I’ll finish this undertaking before another year passes, but with the end of November upon us this is my last post on the Knox Decalogue for this year. So, what have we got?

The detective must not himself commit the crime. This applies only where the author personally vouches for the statement that the detective is a detective; a criminal may legitimately dress up as a detective, as in the Secret of Chimneys, and delude the other actors in the story with forged references.

Perhaps on account of the appointment of the criminal and renowned prison-breaker Eugène-François Vidocq as the head of the first official organised detective force, the Sûreté of Paris, the notion of a criminal-turned-good has long been an appealing touchstone in fiction: Hercule Flambeau in the Father Brown stories of G.K. Chesterton is the literal embodiment of this, of course, but the principle can be found in examples as diverse as the essential morality of Jean Valjean in Les Miserables (1862) by Victor Hugo — whose forthrightness and decency are, after all, the core ingredients of your law-maker — through to Robert Ryan’s turncoat Deke Thornton in Western masterpiece The Wild Bunch (1969). Whoever coined the phrase ‘Send a thief to catch a thief’ knew whereof they spoke.

Curiously, then, for a genre that so delights in the inversion of expectations, Golden Age detective fiction — where the living can be dead and the dead living, the innocent guilty and the guilty innocent, and the impossible done while the probable remains distantly unattainable — has been largely resistant to the notion of the detective-as-criminal. The gentleman thief might be the most accepting the genre has ever been of this conceit — the semi-inversion of someone of means behaving rakishly as if they don’t, a debonair figure disappearing over balconies — with the Scarlet Pimpernel, Raffles, and Arsene Lupin embodying the more successful incarnations, occasionally moved by some deeper sense of social or personal injustice to mollify the readers who might have moral qualms sympathising with a protagonist raised above the level of a common-or-garden yegg by little more than employment of a valet. But, crucially, we knew in advance (or found out fairly quickly) that these gentlemen were malcontents, and it’s what they’ve been known as from the off.

If the Golden Age novel of detection is to be taken as our focus, though, and the revelation of our detective’s wrong-doing is the terminal surprise in the grand scheme…no, sir, this will not stand.

There are obvious reasons for this, and they end up tied to the next two rules in Knox’s list. Firstly, if the detective is detecting their own malfeasance, it remains unlikely that they will admit all the clues honestly — and they may even ‘fail’ to find some of them on account of foreknowledge (fearing, perhaps, that they dropped a tell-tale ear-ring, say, they could opt simply not to undertake a search of the premises). And so, secondly, since our Watson is to be of inferior intelligence to the detective, and since it is the detective who must shine the light of reason upon events, it remains unlikely that the case would ever be solved. Given that the game of the detective novel is predicated on the achievement of a result, and that said result is expected to be the identification of the wrong-doer and their exposure for their crime(s) before all and sundry, any untrustworthiness of the person responsible for guiding us to that solution is to be taken as anathema. If you came for cricket and got Australian Rules Football, you’d be furious.

Now, we can probably all name one novel published during the Golden Age, and almost certainly find at least one per year since, wherein the wrong person is arrested for a crime. In most cases, the ‘correct’ answer to the problem is eventually provided and that innocent party’s blamelessness established beyond doubt. But there is a subset of novels wherein the correct solution remains unknown to the characters within the narrative, and a smaller subset still where the correct solution isn’t explicitly made known to the reader…and, generally, these books frustrate as many people as they delight. One of the drawbacks of rules and tropes in an area of fiction is the absolute certainty with which certain outcomes can be predicted, and sometimes having that taken away it a lot of fun. We love being misdirected about the importance of an action or a phrase, and being misdirected about the intention of a whole narrative is essentially an escalation of that principle. And escalation is a risky prospect: it’s a genre-challenging wrench from “the butler squints at the calendar because he is short-sighted” to “the butler squints at the calendar because it turns out he’s an alien and has no idea how to read any Earth language”, after all.

However, to return to our dishonest detective.

For my money, there’s a fascinating — and no doubt very difficult-to-write — book in a criminal investigating his own crime who, for reasons beyond my imagining, is compelled to be honest about what he uncovers, providing others with the genuine means of spotting his guilt. There are definite examples of a criminal investigating their own crime as a matter of accident — amnesia, say, may have resulted in them forgetting they committed the crime — and some of a criminal knowingly looking into their crime but opting to not reveal what they know, and I’m talking here about the joining of those two. Heaven knows how or why it would happen, but feel free to write that book and thank me in the acknowledgements. Of course, the Unreliable Narrator trope would loom large over proceedings, so any occlusion would have to be genuine…bah, whatever, not my problem.

What would not play in the Golden Age novel of detection would be the detective’s summation of a crime pointing the finger it himself and then proceeding to outline all the ways he deliberately did not declare his clues (see rule 8, when I eventually get round to writing about it). Authors have deployed this trick — I can’t believe there’s much in the genre that someone hasn’t wheeled out at one point or another — but I’m guessing most, if not all, of them sold fewer books second time around. I’ve cited before the example of a locked room mystery in which a big deal is made of how solid four walls of a room are, how locked its door is, how impenetrable its floor, ceiling, and window remain, only for the answer to be that there’s a big ol’ gap between two of the walls, or a fifth wall with a massive hole in it. The expectations — call them rules if you like — are there to guard against this, and to ensure everyone has a fun time.

It’s possible to look at this with the disdainful eyes of the 21st century, in which virtually every single long-running detective character — Harry Hole, Tom Thorne, John Rebus, Charlie Parker, etc., etc. — has some stain on their conscience following some act of questionable morality, and to decide that these old novels were just too out of touch with what people are really like, man. But then it’s also worth remembering that, certainly in the early 2000s, there seemed to be a slew of crime novels in which is was suggested that a long-running protagonist may have been responsible for the setting free of a dangerous criminal who went on to commit untold foul deeds only for it to be revealed — spoilers? — that, oh, actually it turns out you didn’t and so you’re fine. The morally murky is not alien territory to the classic detective — who has sent many a murderer away unpunished, or distracted suspects aplenty with a summation that allows suicide rather than legal justice — in the same way that there still remains an interest in the inherent goodness and rightness of the archetype. The sullying is often token at best (Tom Thorne visited a prostitute once, I seem to remember; John Rebus shut his girlfriend’s cat outside and it got torn apart by a dog, etc.) and any deeper wrongness doubtless justifiable on some knight-errant or fallible-human grounds.

There’s no harm in wanting your detective to be innocent of the crime, either on plot or character association grounds. And on the rare occasions that they are — at the start of one long-running series, and the end of another — it could well be argued, in grand GAD tradition, to simply be the inversion we read this type of story for, anyway. If you’d send a thief to catch a thief, might you need to be a killer to catch a killer…?

~

The rules in the Knox Decalogue as written about by me: