Russia’s Hooligan Army, a 2017 documentary by British filmmaker Alex Stockley von Statzer which explores football hooligans from Russia.
The film raises legitimate points about the safety of foreign fans who will attend the 2018 FIFA World Cup, starting on June 14th. If you have heard anything about football hooliganism in Russia you will know it can get extremely violent; we saw this at the 2016 European Championships when clashes between Russian and English supporters in Marseille erupted. Of course, the Kremlin dismissed this BBC documentary, claiming it was made on a subjective basis.
If you found "Russia’s Hooligan Army" informative, try out the 1999 doc "Chelsea Headhunters" by Irish investigative journalist Donal MacIntyre.