 An early victim is the butler, played by Ballard Berkeley, whose character speaks in a very different voice to Berkeley's normal voice.The murders are investigated by a Scotland Yard detective, played by Lance Percival, and a local Police Sergeant, played by Gastone Moschin, who is probably best known to English-speakers as the white-suited Don Fanucci from The Godfather Part II.The film was set and filmed on location at Somerleyton Hall, both for interior and exterior shots.