Don't read fiction any more so can't recommend much there but it seems you like detective or police related material.
The Onion Field by Joseph Wambaugh is a good book and movie.
LA Confidential is a good noir type movie set in the 1940's with Russell Crowe and Kim Basinger. Basinger won an Oscar for her role here.
A lot of the old Humphrey Bogart classics are great, such as The Maltese Falcon and The Big Sleep in particular. Also lots of the film noir movies of the 40's and 50's like Double Indemnity. They aren't as gritty as modern movies but the stories and dialogue haven't lost anything with age.
Babylon Berlin is an excellent TV series from Germany about a rather conflicted police inspector in the late 1920's Weimar era, it's in German with subtitles but I think there is an English dubbed version as well.
On the somewhat lighter side, Knives Out is a good comedy/murder mystery movie.
