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)