Black Coffee.

Black Coffee is a 1931 British detective film directed by Leslie S. Hiscott. Based on the 1930 play Black Coffee by Agatha Christie featuring her famous private detective Hercule Poirot, it stars Austin Trevor as Poirot with Richard Cooper playing his companion Captain Hastings. A famous but hated scientist, Sir Amory, is killed during a house party, and some of his valuable papers are missing. Poirot rapidly determines the cause of death and the motive, then narrows down the suspects to the most likely culprit.