Find the Blackmailer (1943)

John Rhodes (Gene Lockhart)hires private detective D. L. Trees (Jerome Cowan)to track down a talking blackbird owned by Fred Molner, who uses the bird as a means of blackmailing Rhodes. Molner has taught the bird to repeat "Don't kill me, Rhodes" in the event he is murdered by a member of a gambling syndicate he has defrauded. Going to Molner's apartment, Trees finds him murdered and his bodyguard, Ray Hickey (John Harmon), unconscious. Clues lead Trees to Mona Vance (Faye Emerson, Molner's girlfriend, who is involved with Mark Harper (Robert Kent, presumably her lawyer.