Men of the Night (1934)

"Stake-Out" Kelly, ace detective, meets Mary Higgins at a small Hollywood sandwich shop where he expects to get some information concerning Packey Davis, head of a ring of jewel thieves. His suspicions are confirmed when Mary warns him that Davis is outside - waiting for him. Kelly sets a trap and, in the ensuing battle, one of the gangsters is killed. Davis is interested in rubbing out Kelly as Kelly and Baker are the only two witnesses against Smitty, a Davis henchman. Baker is in the hospital and the plan is bring Smitty there for identification. Kelly accidentally slips the secret to Mary, who in turn innocently informs Packey. A trap is laid.