This refers to the short story "The Tell-Tale Heart" (1843) by Edgar Allan Poe.
The story is narrated by a deranged man, bothered by the old man who lives with him. The narrator finally snaps. He stalks and murders the old man, and hides his remains below the floorboards. The police come to investigate but find nothing unusual, until the narrator begins to hear the heart of the old man beating inside his head--the tell-tale heart. The narrator cannot stand the pounding of the heart, and admits to his crime.