Before Dawn (1933)

Starring Stuart Erwin, Dorothy Wilson, Warner Oland, Dudley Digges, Gertrude Hoffman
Directed by Irving Pichel
(actor & director credits courtesy IMDB.com)

A detective arrests a psychic medium and her father for fraud, but he becomes convinced her abilities are real, and recruits her help in an unsolved murder.

A fun mystery with Erwin an unusually soft-spoken and compassionate detective compared to the usual hard-boiled or wisecracking leads in these films, but what really makes the picture memorable is some creepy imagery near the climax of the film, including the eerie face of a ghost and the revelation of a secret passage and staircase leading to where a fortune may be buried.  There's better written thrillers, but this is a hidden gem of a movie well worth discovering.