The murderer did not think about their conscience taking over and turning the perfect crime into the perfect punishment. Since the murderer does seem to have a conscience that means they cannot be named a sociopath, since the definition of a sociopath is “a person with a personality disorder manifesting itself in extreme antisocial attitudes and behavior and a lack of conscience.” However someone with paranoid schizophrenia would have a conscience, and would definitely have auditory hallucinations like the ringing that they start to hear towards the end of the story “It was a low, dull, quick sound much such a sound as a watch makes when enveloped in cotton.” Soon it is discovered that the noise is the neighbor’s heart ringing in the murderer’s
