It's here, the body is here. Rip up the floor boards.
"His room was as black as pitch" (Poe 80). The old man's room was so dark you could not see a thing. So the psycho could not be seen by the old man.
The narrator explained in detail how he killed the old man. "In a loud scream I rushed towards the old man, he shrieked once-once only. In one quick motion I pulled him off of his bed and put him under it." "He was dead, he was stone dead" (Poe 81).
The narrator felt extreme guilt and anxiety. He confessed to the police what he had done very vehemently and ecstatically.