The narrator is legally guilty of murder, a fact he freely admits, and which seems to be of no interest to him whatsoever. He also appears not to care about his moral guilt. When he explains how it was that he came to kill the old man, he seems to think that his lack of any obvious motive is a point in his favor. His only interest is in what is going on inside his own mind. 

According to the narrator, it was 4:00 a.m. when he had finished skilfully disposing of the body, and three police officers knocked on the door. He smiled and welcomed them in, which is itself an unusual and therefore suspicious response for someone who is visited by the police at 4:00 a.m. To the reader, he professes great confidence, even the “wild audacity” of “perfect triumph,” but very soon, he hears a ringing in his ears, followed by a heartbeat. Whatever this heartbeat really is, and whether or not the police officers can hear it (both subjects of considerable critical debate), there can be little doubt that the volume and significance are greatly increased within the narrator’s own mind. The pressure of psychological guilt leads him to confess to the murder, though even in doing so, he retains his egotistical perspective, accusing the police officers of dishonesty, and calling them villains even as he reveals the act of villainy he has been attempting to hide. This transference of blame may be taken as further evidence of the narrator’s suppressed sense of guilt.