Jim Bannon

Jack Packard

Anita Louise

Janet Mitchell

Michael Duane

Rex Kennedy

Barton Yarborough

Doc Long

Paul E. Burns

Leon Hartman

Thomas E. Jackson

Det. Capt. Quinn

Mona Barrie

Louise Mitchell

Frank Wilcox

Prof. Arthur Logan

Richard Hale

Curator Raymond Halliday

Ludwig Donath

Dr. Karger

Mary Newton

Nurse

Edward Earle

E. R. Willard

Fred Godoy

Senor Mendoza

John Elliott

John, butler

Frank Mayo

Quentin Mitchell

Frank Martin

Introductory Narrator (voice)

Coulter Irwin

Frank, Willard's aide

Bud Averill

Closing-Time Museum Guard

Harry Strang

Brophy, museum watchman

I Love a Mystery

The Devil's Mask

The Unknown