Torchy Blane in Chinatown (1939)

Newspaper reporter "Torchy" Blaine and police detective Steve McBride are on the trail of an Oriental gang that has committed three murders. Also on hand is a fabricated Scotland Yard operative who is a phony, and has two others assisting him in an effort to throw the police department off the trail; they are trying to exhort $250,000 from a young rich man who is trying to marry a senator's daughter. A submarine gets involved.