Ralph Bellamy
Ellery Queen
Margaret Lindsay
Nikki Porter
Charley Grapewin
Insp. Queen
Mona Barrie
Nurse Marian Tracy
Paul Hurst
Page
James Burke
Sgt. Velie
Leon Ames
John Stack
George Zucco
Dr. Edwin L. Jannery
Blanche Yurka
Mrs. Augusta Stack
Charlotte Wynters
Miss Fox
Tom Dugan
Lou Thomas
Olin Howland
Dr. Williams
Dennis Moore
Dr. Dunn
Jean Fenwick
Alice Stack
Pierre Watkin
Crothers
Byron Foulger
Hospital Orderly (uncredited)