Behind the Mask

Jack Holt

Jack Hart aka Quinn

Constance Cummings

Julie Arnold

Boris Karloff

Jim Henderson

Claude King

Arnold

Bertha Mann

Nurse Edwards

Edward Van Sloan

Dr. August Steiner / Dr. Alec Munsell / Mr. X

Willard Robertson

Capt. E.J. Hawkes

Thomas E. Jackson

Agent Burke

Martha Mattox

Hotel Ansonia Maid

Jessie Arnold

Eastland Hospital Nurse

John Francis Dillon

Director

Ted Tetzlaff

Director of Photography

Otis Garrett

Editor

Harry Cohn

Producer

Edward Sloman

Assistant Director