Murder by Death

Murder by Death is a 1976 American mystery comedy film with a cast featuring Eileen Brennan, Truman Capote, James Coco, Peter Falk, Alec Guinness, Elsa Lanchester, David Niven, Peter Sellers, Maggie Smith, Nancy Walker, and Estelle Winwood, written by Neil Simon and directed by Robert Moore.

A group of five renowned detectives, each accompanied by a relative or associate, is invited to dinner and a murder by the mysterious Lionel Twain. Having lured his guests to his mansion managed by a blind butler named Jamessir Bensonmum, who is later joined by a deafmute cook named Yetta, Twain joins his guests at dinner. The house is then sealed off. Twain announces that he is the greatest detective in the world. To prove his claim, he challenges the guests to solve a murder which will take place at midnight a reward ofmillion will be presented to the winner.Before midnight the butler is found dead and Twain disappears, only to reappear dead from a stab wound immediately after midnight the cook is also discovered to have been an animated mannequin, now packed in a storage crate. The party spends the rest of the night investigating and bickering. They are manipulated by a mysterious behindthescenes force, confused by red herrings, and baffled by the mechanical marvel that is Twains house, and they ultimately find their own lives threatened. Each sleuth presents his or her theory on the case, pointing out the others past connections to Twain and their possible motives for murdering him. ........

Source: Wikipedia