Watch Citizen X for Free: How to Stream the Movie Online at 123Movies. . Based on the true story of a Russian serial killer who, over many years, claimed victim to over 50 people. His victims were mostly under the age of 17. In what was then a communists state, the police investigations were hampered by bureaucracy, incompetence and those in power. The story is told from the viewpoint of the detective in charge of the case.