The narrator is explaining his plan, and is talking about why he wants to kill him. "It is his eye, it looks like a raven with a shield over it. That was the reason. I am not crazy I am smart, he will never expect it." He is trying to convince you he is smart, not crazy.
He is now staring at the man in his sleep. He has been doing it for 7 nights, but not killing him because he could not see his eye. So very night at 12:00 he would stare at the man from the door way not knowing when he was going to kill him.
The narrator does not like the old man's eye.
The old man wakes up in fear. The narrator, not moving a muscle, while in the door way. They do this for a while, until the narrator comes in. He hears the heartbeat of the man. It keeps getting faster and faster. The narrator can not handle the sound anymore and suffocates the old man with his mattress from his bed. Then, he cuts up the old man and puts the body bucket so there is no trace of blood and sticks the cut up body under a floor board.
There is a knock at the door. The narrator opens the door with confidence inviting the two in. He even places a chair over the body and sits there, letting the officers look through the house. The narrator starts hearing a terrible sound, the heartbeat of the man. It is taunting him and getting louder.
The narrator can not handle the heartbeat anymore, so he confesses what he did to the poor man. He showed them everything and where he hid the body.