SPOILER ALERT: the following article contains massive spoilers, including the ending. If you have not yet seen the movie, proceed at your own risk, or better, come back to this article later!
SPOILERS AHEAD
Memories of a Murderer: The Nilsen Tapes Plot Summary and Synopsis
Serial killer Dennis Nilsen narrates his life and horrific crimes via a series of chilling audiotapes recorded from his jail cell.
Source: Wikipedia (CC BY-SA 3.0).