As macabre as it sounds, I really enjoyed seeing Doris Day (The Man Who Knew Too Much) get terrorized. She was so convincing in this role especially when she provided a tour de force in acting during that scene where she finally breaks down. I can't believe other commentators were not as moved by this as I was. Rex Harrison (The Ghost and Mrs. Muir, Cleopatra, My Fair Lady) is also very good in this role though I don't think he is challenged very much here. John Williams is once again the diligent inspector as he was in the two Alfred Hitchcock hits Dial M For Murder and To Catch a Thief, both of which coincidentally starred Grace Kelly. The great Roddy McDowell (Planet of the Apes) is here just as a red herring but he is welcome nonetheless. All in all a good thriller, 8/10.