Edgar Poe uses an unreliable narrator. The narrator retells the murdering of the old man as if the crime would dismiss him from his sanity. I assume the narrator to be male but in ways the narrator can be female as well but it isn't clarified to go one way or the other. At the beginning, it could be that he/she is confessing to a judge, cellmate, newspaper, or psychiatrist and feeling the need to express themself in great detail to prove that he/she is in fact sane. The narrator's personality appears to be normal until the old man's "vulture eye" begins to haunt them, it is then they seem to have a real psychological problem because they have the motivation to kill the innocent old man because of his eye and for no other reason. The narrator had no problem with him."I loved the old man. He had never wronged me."(Poe 37.) But in the end the narrator is clearly sick as he/she can hear the old man's heart beating through the floorboards out of guilt and dramatically confess to the police that they murder the old man.