Serial Killer Documentaries: “Memories of a Murderer: The Nilsen Tapes” Told through a series of audiotapes recorded in a jail cell, "Memories of a Murderer: The Nilsen Tapes" looks at the murders of Dennis Nilsen, a former police officer who killed at least 12 young men and boys in London between 1978 and 1983. Watch "Memories of a Murderer: The Nilsen Tapes" on Netflix. Image Source: Getty / Harry Dempster