Mister Dynamite (1935)

San Francisco private-eye T. N. Thompson (aka T.N.T., aka Mr. Dynamite), a reckless black-balled investigator who is given a police escort out of most towns, is hired by the owner of a casino to investigate the murder of a young man as he left the grounds. Before Thompson can solve the first murder, two more occur, and the police refuse to help him in his investigation of all three.