Dashiell Hammett, "Slippery Fingers" (1923) from Dashiell Hammett: Crime Stories & Other Writings:
Hammett's Continental Op only has a few descriptors: he’s fat, nameless, determined. And in this story, we can see that he occasionally loses his temper. While the character and setting are American noir, the story is again a semi-throwback to English problem stories: here’s a dead man who mysteriously withdrew some money from the bank and though there are fingerprints all over the crime scene, the police can’t find the matching set.
That is, they can’t find the matching set until the killer walks in the door and demands to be fingerprinted. See, the killer was a blackmailer who saw the rich man kill a guy among the gold fields of the North; and he demands to be fingerprinted because he has a false set of fingerprints on; and the Continental Op only discovers this because he gets angry and tries to get the man’s fingerprints instead of letting the fingerprinting expert do it. (Why'd the finger-printing expert miss it in the first place?)
Which leaves us a mystery story where the protagonist has discovered the killer--but only through the bad luck of the killer and his own good (dumb) luck. This may be fitting since this is a story about horse-racing and mining, two pretty luck-dependent fields. And there’s enough Hammettian humor and overstatement to keep the story moving briskly: the forensic accountant can spot a bad set of books farther than the Continental Op can see the books; and the final scene is the fingerprint sharper and the fingerprint expert discussing the ins and outs of their specialized trade, even though the fingerprint sharper has just been busted and is probably going to jail for a while.
But for all that, the story is a relatively simple quest to find the murderer--where the murderer basically turns himself in. And for all the promise of violence and the underworld, so much of this is squeaky clean and bloodless. I will say this: since the Continental Op is supposed to be so good at his job, we pretty much always trust him when he sizes up people, especially since his sizing is a mix of good and bad.