A court in Moscow has sentenced the leader of a notorious Russian organized crime gang to life in prison for involvement in at least 20 killings. The Moscow City Court judge said Tuesday that Sergei Butorin posed a grave danger to society and should be incarcerated for the rest of his life. ITAR-Tass news agency quoted the judge as ruling Butorin had been behind 20 murders and nine attempted killings. Butorin headed the Orekhovskaya gang, an organized criminal group that reached the height of its powers in Moscow in the 1990s. He was arrested by Spanish authorities in 2001 on charges of trading in illegal weapons and extradited to Russia last year. Russian criminal groups flourished in the chaotic years that followed the fall of the Soviet Union in 1991.