It takes the narrator of “The Tell-tale Heart” a total of eight days to carry out his plan, but he actually kills the old man in one night—and gets caught the next morning.
I was never kinder to the old man than during the whole week before I killed him. And every night, about midnight, I turned the latch of his door and opened it—oh so gently! (ch 4)
The narrator takes a very, very long time to stick his head through the door. It took an hour to get his head through. On the eighth night the narrator finally acts. He takes care in opening the door, and the old man sees him and shrieks. He then throws the bed on top of him.
But, for many minutes, the heart beat on with a muffled sound. …. At length it ceased. The old man was dead. I removed the bed and examined the corpse. Yes, he was stone, stone dead. (p. 5)
The narrator cuts the old man up and sticks him under the floorboards, and then police arrive because they have heard the old man’s scream. The narrator lets them in, asks them to look around, and has them sit in the old man’s room above the body.
They talk for a time, but the narrator is getting more and more anxious. At first he just wanted to prove that he was not guilty, but the imagined sound of the dead man’s heart gets to him and he confesses.