Poe's "The Tell-Tale Heart" is arguably one of his most disturbing. The action unfolds this way.
First, the narrator tells us that he believes the old man with whom he lives has an "evil eye." The eye is weirdly cloudy and sight of it drives him literally insane (or so he thinks is the cause.)
The narrator decides that the only way to be rid of the sight of the eye forever is to kill the old man. The narrator sneaks into the man's room at night, but cannot bring himself to murder him until he has one more look at the eye.
The old man, however, sleeps soundly. It is not until the eighth night that he awakens. Sensing someone in his room, he fears (rightly so, but not for the reasons he believes) that "Death" is approaching.
The narrator goes berserk. He thinks the loudness from terror of the old's heart will betray him. He carries out his hideous plan, but it goes afoul when the narrator believes the heart beats on.
He decides to dismember the man and bury him beneath the floorboards.
Alerted by the scream of the old man, neighbors *do* become wary and call the police. The narrator tries to rid them, but they do not leave. The longer they stay, the more agitated the narrator becomes. In his mind, the beating heart becomes so unbearably loud that he finally screams out his confession: "I admit the deed!—tear up the planks!—here, here!—it is the beating of his hideous heart!"