The narrator is vexed by the old man's eye, but he still loved the old man.
Every night the narrator went into the old man's room at midnight to try to get tid of the eye but it was always closed
On the last night the old man woke up and the narrator thought he heard the old man's heartbeat and that the neighbors would hear it, but really it was his heartbeat so with audacity he decided to kill the old man so he wouldnt be caught.
The narrator dissembled the body and hid any evidence
The police officers came by and the narrator told them they could search well.
The narrator thought the police officers would hear a beating that he heard and he would be caught, so he showed his deed and it really was the beating of her heart.