Kadro (21)
Ralph BellamyEllery Queen
Margaret LindsayNikki Porter
Charley GrapewinInsp. Queen
James BurkeSgt. Velle
Michael WhalenDr. James Rogers
Marsha HuntBarbara Braun
Fred NibloJohn Braun
Charles LaneDr. Prouty
Ann ShoemakerLydia Braun
Marion MartinCornelia
Douglas FowleyRocky Taylor
Morgan WallaceZachary
Byron FoulgerAmos
Katherine DeMilleValerie NorrisPeter BronteDoctor's Assistant (uncredited)
Jack CheathamDesk Sergeant (uncredited)Arthur MillettElevator Guard (uncredited)
Frank O'ConnorAmbulance Driver (uncredited)
Lee PhelpsFlynn (uncredited)
Alan LaddElevator Passenger (uncredited) (unconfirmed)
Jack RiceRogers' Assistant (uncredited)