Alfred Hitchcock Presents: The Right Kind of House (1958)

Mr. Waterbury in interested in buying a high priced house. Sadie Grimes, the house's owner, invites Waterbury in for a drink. She says the price is nonnegotiable. The place has strong sentimental value for Sadie: her son was killed there over a mysterious bag that has since never been found. She believes the bag contained money which is hidden somewhere in the house. Waterbury says he will buy the house despite its inflated price. Sadie accuses him of being her son's murderer. Waterbury confesses that he is the murderer, but he slumps over dead. His drink had been poisoned.