PATHOLOGY

Detailed explanation-1: -He believes that he hears the old man’s heart beating. He may, however, be hearing the victim’s watch ticking or his own heart. Why does the narrator confess to his crime? He thinks the officers hear the same sound as he does, and he wants to get away from the sound, so he confesses.

Detailed explanation-2: -He says that he hears the old man’s heart beat.

Detailed explanation-3: -The murder is carefully planned, and the killer killed the old man’s by pulling his bed on top of the man and hiding the body under the floor. The killer feels guilty about the murder, and the guilt makes him imagine that he can hear the dead man’s heart still beating under the floor.