Berezovsky, once Putin's ally, is now one of his fiercest critics. He, along with former Chechen rebel commander and foreign minister of the Chechen government in exile Akhmed Zakayev (left), were part of Litvinenko's inner circle in London.
Here's Berezovsky's timeline:
With Perestroika under way Berezovsky enters the business world. He will go on to become Russia’s first billionaire. He was rumored to be targeted by the Russian mafia due to his connections with Chechen mafia.
Berezovsky survives a car bomb attack. The FSB assigns Litvinenko to investigate, and the two become friends.
Berezovsky forms a group of oligarchs, the Big Seven, to bankroll Yeltsin’s election campaign. The Big Seven controlled most of the media outlets, awhich become dedicated to "all Yeltsin all the time".
In a Forbes article Godfather of the Kremlin? American journalist Paul Klebnikov (left) portrays Berezovsky as a mafia boss who had his rivals murdered. Berezovsky sued the magazine, which then retracted the claims.
Klebnikov is assasinated in Moscow in 2004.
Litvinenko goes public with claims that the FSB order him to assassinate Berezovsky
Berezovsky elected to Duma. Although he supported Putin’s campaign for the Presidency, he was opposed to the Second Chechen War.
Berezovsky sets up Liberal Russia party. Putin begins investigating him for corruption, and Berezovsky escapes to London. Alex Goldfarb (left), Berezovsky's right-hand man and Chair of his International Foundation for Civil Liberties, helps Litvinenko and his family flee Russia. Litvinenko moves into Berezovsky's north London house.
Berezovsky goes into business with Neil Bush, the younger brother of the US President.
Berezovsky formally changed his name to Platon Elenin
Berezovksy claims that Chechen separatists have acquired a portable nuclear bomb, and only lack one “minor detail. Recent speculation is that polonium-210 could be that minor detail.
Berezovsky helps finance Ukraine’s Orange Revolution and the campaign of president Viktor Yushchenko.