Tim Bell, CEO of Bell Pottinger Private Relations, confirmed to the media the mysterious death of Russian tycoon Boris Berezovsky, who was found dead in a bathroom in his home outside London.

A bodyguard made the discovery during the evening of March 23.

The 67-year-old former math teacher was a member of Boris Yeltsin’s inner circle. He helped install Vladimir Putin to power but later became the Russian president’s enemy No. 1.

Berezovsky, who fled Russia for the U.K. in 2000, was tried and sentenced in absentia for fraud and political corruption seven years later.

He claimed the Russian government attempted to assassinate him. That charge was denied.

Berezovsky’s bodyguard died in 2006 after drinking tea laced with radioactive plutonium at a London hotel. The Kremlin also denied any link to that murder.

London police swept Berezovsky’s home for nuclear, biological and chemical threats. The house was declared clean.

An official cause of death has not been made.