Mildred NatwickNadia Demarest Eileen HeckartMrs. Haskell Judith EvelynMrs. Collins Walter SlezakDr. Potterton / Richard Morley Leslie NielsenSerge Soudekine Richard CooganInvestigator Westcott Morton StevensMr. O'Farrell Sidney BlackmerDr. Steven Archer Olive DeeringMuriel Torres Eva GaborMadeleine De Rochefort Robert H. HarrisDr. Tabor Martin E. BrooksMeros Leckow Jeffrey LynnJohn Bantreagh Ray WalstonTicket Seller (uncredited) Otto KrugerChester Crabtree Marjorie GatesonFlorence Hackett Neva PattersonKelly Davis Luis van RootenPolice Inspector Jules Maigret Basil RathboneDr. Jekyll / Mr. Hyde Jack PalanceCount Alessandro di Cagliostro Thomas MitchellHenry Brown Eddie AlbertDanny Maguire Louisa Horton HillSally Turner Edmon RyanDistrict Attorney Russell CollinsEverett Kelsey Frank MarthLt. Captain Richter Patrick McVeyHarry Martin George MathewsPolice Detective Dana WynterPatricia Richter Isobel ElsomMrs. Cattermole Robert EmhardtMorgan Nelson Susan DouglasZita Bradford Felicia MontealegreElaine Bela LugosiGen. Fortunato Warren StevensBernard Frank Richard FraserClub President Otto PremingerCaptain von Weissenborn Virginia GilmoreCora Maybee Cornell WoolrichSchrijver Max Simon EhrlichSchrijver Charles RobinsonSchrijver 
