Kadro (16)
Ralph BellamyEllery Queen
Margaret LindsayNikki Porter
Charley GrapewinInsp. Queen
Mona BarrieNurse Marian Tracy
Paul HurstPage
James BurkeSgt. Velie
Leon AmesJohn Stack
George ZuccoDr. Edwin L. Jannery
Blanche YurkaMrs. Augusta Stack
Charlotte WyntersMiss Fox
Tom DuganLou Thomas
Olin HowlandDr. Williams
Dennis MooreDr. Dunn
Jean FenwickAlice Stack
Pierre WatkinCrothers
Byron FoulgerHospital Orderly (uncredited)