Self-exiled Russian oligarch Boris Berezovsky has died in London, his son-in-law, Yegor Shuppe, said on Facebook Saturday.

The circumstances around the death of Berezovsky, a well-known critic of the Kremlin since 2000, were not immediately known.

Berezovsky made headlines in recent years over various business deals and legal disputes, including a libel case against a Russian broadcaster. All-Russian State Television and Radio Broadcasting Company (VGTRK) claimed in a report that Berezovsky was behind the 2006 poisoning death of former Russian spy Alexander Litvinenko.

Berezovsky won that claim, and the High Court in London awarded Berezovsky £150,000 ($223,400) in damages.