The Telltale Heart.

An insane man first loves then grows to hate his neighbor, an old man whose penetrating gaze unnerves the insane man. He plans a perfect crime and executes it one night. The next day, two officers knock on the insane man's door, investigating a shriek heard in the night. The insane man invites them in, answers their questions, and submits to an examination of his eyes by one of the officers, who proclaims him innocent. The insane man invites them to stay and relax awhile, then regales them with his theories of crime. His heart begins to beat louder. Angles on the set are skewed to suggest the man's internal disarray.