quality:correction, linguistic:paraphrasing
Boris Abramovich Berezovsky, also known as Platon Elenin, was a Russian business oligarch, government official, engineer and mathematician and a member of the Russian Academy of Sciences. He had the federal state civilian service rank of 1st class Active State Councillor of the Russian Federation. Berezovsky made his fortune in Russia in the 1990s, when the country implemented privatization of state property. He profited from gaining control over assets, including the country's main television channel, Channel One. In 1997, Forbes estimated Berezovsky's wealth at US$3 billion. Berezovsky helped fund Unity, the political party that would form Vladimir Putin's first parliamentary base, and was elected to the Duma in the 1999 Russian legislative election. However, following the Russian presidential election in March 2000, Berezovsky went into opposition and resigned from the Duma. Berezovsky would remain a vocal critic of Putin for the rest of his life. In late 2000, after the Russian Deputy Prosecutor General demanded that Berezovsky appear for questioning, he did not return from abroad and moved to the UK, which granted him political asylum in 2003. After he moved to Britain, the Russian government took over his television assets, and he divested from other Russian holdings. In Russia, Berezovsky was later convicted in absentia of fraud and embezzlement. The first charges had been brought during Primakov's government in 1999. Despite an Interpol Red Notice for Berezovsky's arrest, Russia repeatedly failed to obtain the extradition of Berezovsky from Britain; the situation became a major point of diplomatic tension between the two countries. In 2012, Berezovsky lost a London High Court case he brought over the ownership of the major oil producer Sibneft, against Roman Abramovich, in which he sought over £3 billion in damages. The court concluded that Berezovsky had never been a co-owner of Sibneft. Berezovsky was found dead in his home, Titness Park, at Sunninghill, near Ascot in Berkshire, on 23 March 2013. A post-mortem examination found that his death was consistent with hanging and that there were no signs of a violent struggle. However, the coroner at the inquest into Berezovsky's death later recorded an open verdict.