Plumbum, or The Dangerous Game(1987)

Original title: Плюмбум, или Опасная игра

Fifteen year old gifted teenager Ruslan Chutko longs to do good and help the police to identify offenses under the pseudonym Plumbum. Plumbum decides in a single provincial town to eradicate the evil. However, in his interest of being a fighter against evil he goes far beyond what is permitted in a children's play and ends up ruthlessly invading people's lives.