Claim: Stranger on the Third Floor is a 1940 American film noir directed by Boris Ingster that is about a murder of the main protagonist's neighbor.
Evidence: Stranger on the Third Floor is a 1940 American film noir directed by Boris Ingster and starring Peter Lorre, John McGuire, and Margaret Tallichet, and featuring Elisha Cook Jr.. Ward feels that his neighbor, a man he hates, may have been killed by the stranger.