The narrator explains at length his theory on which he believes causes people to commit acts against their self-interest. This essay-like discussion is presented objectively, though the narrator admits that he is "one of the many uncounted victims of the "Imp of the Perverse". He then explains how his conviction for murder was the result of this. The narrator murders a man using a candle that emits a poisonous vapor. The victim enjoyed reading in bed at night and, using the candle for illumination, dies in his poorly-ventilated room. No evidence is left behind, causing the coroner to believe the man's death is an act of God. The narrator inherits the man's estate and, knowing he can never be caught, enjoys the benefits of his murderous act for many years…
(Excerpt from Wikipedia)