Before Dawn

Stuart Erwin

as Dwight Wilson

Dorothy Wilson

as Patricia Merrick, also known as Mlle. Mystera

Warner Oland

as Dr. Paul Cornelius

Dudley Digges

as Horace Merrick

Gertrude Hoffmann

as Mattie (as Gertrude W. Hoffman)

Oscar Apfel

as Chief of Detectives John F. O'Hara

Frank Reicher

as Joe Valerie

Jane Darwell

as Mrs. Marble

Stanley Blystone

as Police Car Driver (uncredited)

Ed Brady

as Paddywagon Cop (uncredited)

Tom Brower

as Detective Schultz (uncredited)

Pat O'Malley

as Detective Brady (uncredited)

Ted Oliver

as Police Desk Sergeant Hamilton (uncredited)

Irving Pichel

as Police Radio Announcer (voice) (uncredited)

Max Wagner

as Policeman in Car (uncredited)