Why worry about prison when you've got connexions on the parole board? By the 1940s, quick turn-arounds for prison inmates were notorious in many places throughout the U.S., and so Hollywood made 1948's Parole, Inc. Called a film noir by Wikipedia*, it's really not. It's a simple, short crime film, "ripped from the headlines," as they say. It's no masterpiece but its ambitions aren't even that high. It succeeds at being pretty good.
Federal Agent Richard Hendricks, played by a sharp and cagey Michael O'Shea, decides to go undercover as a bank robber so he can trace the line of underworld connexions to whomever's bribing the local parole board. The film goes step by step through his decently smart plan--he assumes the identity of a real thief but uses an alias, allowing the gangsters at hand to snoop and find out his "real" name. He lets slip that he knows a certain comrade of the thief he's posing as and everything works.
If this really were a film noir, he'd get mixed up with a dame or become fast friends with one of the crooks, there'd be betrayal and existential confusion. There's none of that here, Richard just does his job, straight down the line, and doesn't even lose his wits when the beautiful lady in charge of the gang, Jojo (Evelyn Ankers), demands his kisses as payment for assistance.
It's a bit surprising to see a woman portrayed as the boss though she turns demure when a real heavy takes charge in the form of a lawyer named Rodescu (Turhan Bey). The climax of the film has some effective tension when Richard executes a tricky plan at Rodescu's summer house.
Parole, Inc is available on Amazon Prime.
*The Wikipedia entry was edited in 2017 to add the film noir label. Nowadays even musicals are getting called films noir. There's a generation now that thinks any old movie where people wear fedoras is a film noir.