4. Tales of the Grim Sleeper
IMDb Rating: 7.1
Tales of the Grim Sleeper that ranks 4th on our list of serial killer documentaries on YouTube explores the life and crimes of Lonnie David Franklin Jr. who committed at least 10 murders and attempted one. First 7 murders happened between 1985 and 1988, and last three happened between 2002 and 2007. All of his victims were black women.