Charlie Chan at the Circus (1936)

Charlie receives fourteen free passes to the circus for him and his entire family but soon realizes that there are strings attached as the big top's co-owner asks his guest to investigate threatening letters that he's received. Before the famous detective can, the man is murdered. Charlie soon finds out that the co-owner was not a particularly pleasant or well-liked individual, and among the many suspects are his partner, a snake charmer and the menagerie's gorilla. Son Lee, usually an enthusiastic assistant for his father, is distracted by the show's beautiful contortionist.