Having thoroughly enjoyed some of the entries Dennis Lynds wrote as William Arden in the Alfred Hitchcock and the Three Investigators series, I was surprised and curious when I discovered that he had written an impossible crime story listed in Adey, ‘The Bizarre Case Expert’ (1970). Rigour isn’t always Arden’s jam, so how did he apply himself here?

Somewhat akin to Roy Vickers’s Department of Dead Ends, what we have here is Central Squad, where all the problematic cases get sent before being filed as unsolved.

Central gets anything that stumps the precinct squads — or what we call the “circus cases”. Or, to be more exact, I get them…

Detective Sergeant Joseph Marx — “the one-man Circus Case Squad” — is getting something of a reputation for dealing with these seemingly bizarre and insoluble problems, and this latest one might be the most bizarre yet. Encountering a noise complaint against an unpopular tenant of a salubrious apartment block, two patrolmen go to investigate only to find the accused apartment ominously quiet. The door is opened with a passkey but found to be chained on the inside, so they kick their way into the flat and discover the shocking truth: the whole apartment is in disarray “from some violent struggle”, Mrs Sally Tower has been beaten to death, and her ex-husband is unconscious in the room with her.

So far, so classic.

It’s established fairly quickly that the window to the fire escape is open, upsetting the lockedness of this apparently locked room, and once the unconscious man regains his wits he gives a statement to the effect that someone climbed through the window from the fire escape, knocked him out and must have killed his ex-wife. “Looks like a routine killing by a prowler, that’s all,” Marx says. But he’ll be very wrong indeed.

“A Mrs. Miller in apartment 1-B stated that she’d been sitting at her window below the fire escape all evening. She’s an invalid. She likes to look out of that window. She saw no-one go up or come down the fire escape all night. Everyone else with a window facing the fire escape was home. And no prowler entered their apartments.”

So no-one could have gone in or out of 6-B without going through the fire escape window, but Mrs. Miller and others are able to confirm that no-one did any such thing.

The classical locked room. Only there isn’t any such thing. There’s always an explanation. Except in this case I couldn’t see one.

Arden paints his scenes well, with enough sprinkling of atmosphere to count (“Mrs. Tower had been in the thick of the latest fad for odd decoration and old-fashioned ugliness…”). You can see how his economy of style compelled him as a writer of books for younger readers, with no unnecessary filigrees to complicate matters, and his prose is clean throughout. This is additionally important when, with a simple paragraph here and there, he adds further complications and then explodes the prowler theory even more neatly than any possibly-fallible witnesses ever could. The question is: how to make sense of this seemingly senseless, seemingly impossible crime?

There’s a risk here that you go the same route as ‘The Invisible Man’ (1911) by G.K. Chesterton and ruin that lovely setup, but Arden is wise to that and does his best to take it off the table quickly. There’s also the spectre of ‘The Invisible Weapon’ (1928) by Nicholas Olde lingering here, but Arden has a different tack in mind again: I don’t know if it’s original, how he cleans up his various messes, but it certainly feels like something which has adapted the principles of the Golden Age and updated them into the era this was written. I don’t love it, but I can’t deny that it’s both clever and deals with the contradictions inherent in the story well.

Additionally — and this is a minor consideration — it’s an easily-parsed idea that builds on the inherent simplicity of the prose and the structure of this one. I can’t believe many Three Investigators fans would have even been aware of Arden as the author when younger, but if they were moved to pick this up purely through familiarity with his name and interested to see what he did elsewhere, well, they could certainly have a worse introduction to the impossible crime. It’s a fun, quick, nicely-limned story that makes me wish Arden had followed it up with a whole series. Alas, not to be, but this is certainly worth checking out if you get the chance.