Oh my god, you're RIGHT.

A man murders his neighbor, an old man, and stores his heart underneath the floor. As days past, he continues to hear the heartbeat of the old man's heart. One day, two police officers come over to the man's house to investigate the disappearance of the old man. The longer they're there, the louder and louder the heartbeat gets, until the man can no longer take it and reveals that he murdered the old man, and hid his heart underneath the floorboards.