Murder by Death

This is a spoof film, featuring the top private investigator characters of the time, you will probably only know Poirot.
Unfortunately, the film does have an Asian detective played by a white actor in yellow-face; the depiction is racist, but we think it is important to see and have knowledge of what was once common in films.
This film definitely inspired the much better film Clue, and interestingly both films feature Eileen Brennan.
Features a very young Maggie Smith, Truman Capote, Eileen Brennan, Alec Guinness, and others.