Catching Up: Red Harvest by Dashiell Hammett, 1929, Overdrive download and I do not recall the copyright on that one.
The Continental Op makes his famous trip to Personville. Personville is known across the West as Poisonville because it is a rotten town run by a local mine owner who has paid off everyone in town. The cops are on the take. The crooks are crooked. The papers are bent. The politicians are paid off.
The Continental Op is sent to Poisonville when the local newspaper editor hires the Continental Detective Agency. The Op arrives by train and discovers grey buildings grouped into a grey town and surrounded by grey mountains. The city's dominant features are grey (obviously) and tall smelter chimneys. The Op keeps an appointment with the Editor at the Editor's home, but the man is not there. The Op meets the wife. The wife answers the telephone, leaves the house, and returns a half-hour later. The Op is sent back to his hotel.
The Op discovers that the Editor was shot to death. Well, that's a trick. The Op is curious and visits with Mean Old Man who runs Poisonville. Mean Old Man, MOM, is upset is son is dead. MOM wants to hire the OP to clean things up. Op knows this is sketchy. Op knows that MOM wants to get the men who killed his son, he doesn't really want things cleaned up. Op negotiates payment and a deal that the Op won't stop until the dime does drop. (Best rhyme I have.)
Things start quick with Op figuring out how to get the various criminal factions fighting. He lies and schemes his way into their confidence and sets the many sides against one another. Bootleggers, pimps, con men, numbers racketeers, robbers, burglars, and a bent Police Chief. Mob girl Dinah Brand becomes the OP's inside source.
The Op does not handle things ethically or legally. He shoots a couple men and sets other men up for beatings and shootings. A turning point is when the Op wakes up from an alcohol blackout to see he is lying (laying?) next to Dinah and holding the icepack used to kill her. Op wonders if he killed her. As the novel moves on his judgment becomes more questionable and he describes his actions as "blood simple". The Op doesn't want anyone arrested and prosecuted, he just wants them dead. He's been drinking the Poisonville water and he's becoming like the dirtbags he is working against.
Anyhoo. It's worth your time as both a classic and good novel. I suggest reading the book. I think the prose works better on the page than in the ear.