Falcon Takes Over, The (1942), directed by Irving Reis.
An oddity of history is that the first Raymond Chandler novel to be filmed was this entry in the Falcon series. They must have been desperate for scripts and decided give this Chandler guy a try, doing a condensed Farewell, My Lovely, perhaps his best novel.
George Sanders had made a series of "The Saint" movies about a gentleman sleuth. Tired of paying royalties RKO turned him into "The Falcon" and continued, a change in name only.
We have only 63 minutes for the story and moreover have to shove in extra RKO comedy characters: James Gleason as head of Homicide, Edward Gargan as his flunky, and Allen Jenkins as the Falcon's sidekick. Shakespeare had the same problem: even in the tragedies the troupe's clowns had to have work.
Even so the skeleton of the plot is there:
Moose Malloy is out of prison and searching for his girl Velma. He leaves a trail of bodies, not knowing his own strength.
Just as Marlowe/The Falcon becomes interested, another case comes his way, a diversion and a trap.
A side trail leads to a society psychic.
Moose finds Velma, who has been hiding in plain sight.
The changes:
Moved from LA to NYC.
Black-owned "Florians" is now a the high-end "Club 13".
We drop the section where Marlowe is sapped, drugged, and thrown into a residential treatment prison.
We lose the gambling boats.
Additional cast:
Ward Bond (uncredited) as Moose Malloy. He's very good.
Lynn Bari as Ann Riordan, who shows up just when Marlowe needs her, suspicious both in the book and the movie.
Turhan Bey (uncredited) as Jules Amthor, the psychic.
Hans Conried age 25 (uncredited) as Marriot, a middleman.
Score by Roy Webb.
Filmed again as:
"The Saint" and "The Falcon" series are available in DVD boxed sets.