Erle Stanley Gardner. The Case of the Backward Mule (1946) 250 pp.
Terry Clane, an expert in the ways of the Orient, returns to San Francisco after another extended stay in China and is promptly picked up by the police. His former girlfriend, Cynthia Renton, is being sought for questioning. Her fiancé, Edward Harold, who has been convicted of murder of businessman Horace Farnsworth and sentenced to the gas chamber at San Quentin, has just escaped police custody and is a fugitive. Clane, with the help of several Chinese friends, turns amateur sleuth in order to protect Cynthia and help Harold, who he believes is innocent and stands a good chance of having his conviction overturned on appeal. With the police following him, Clane uncovers another murder and leads them on a chase through the dark alleyways and secret passages of Chinatown before he solves the mystery.