The Narrator looking at the old man's vulture eye and deciding to kill him.
The Narrator watched the old man sleep for 7 nights, being careful not to wake him
On the eighth night, he was more cautious than usual, but his hand slipped on the lantern and woke the old man
The old man woke up and was scared, he lay in bed awake for the next hour while the narrator waited.
The narrator then killed the old man, drained the blood in a tub, cut up the body, and put the pieces of the body under the boards of the house it the living room.
Police came because someone heard a scream come from the house and called the police. The police stayed and talked and looked around the house until the narrator heard a heartbeat, the heartbeat of the old man they killed. It got louder and louder until the narrator confessed and said that they killed the old man.