Murder in Three Acts (1986)

Hercule Poirot's (Sir Peter Ustinov's) assistant, Captain Arthur Hastings (Jonathan Cecil), calls him down to Acapulco, Mexico, where he can write his memoirs, but Hastings drags him to a party populated with Hastings' new friends. There's Janet Crisp (Concetta Tomei), the writer, Daisy Eastman (Marian Mercer) and her daughter "Egg" (Emma Samms), Ricardo Montoya (Fernando Allende), Dr. Strange (Dana Elcar), Miss Milray (Frances Lee McCain) the housekeeper, and Charles Cartwright (Tony Curtis) the famous American actor. But at the party another guest, Reverend Babbington (Philip Guilmant), dies from poisoning and when Dr. Strange also dies from poisoning, Poirot must swing into action before the serial killer strikes again.