London ? The richest man in the former Soviet state of Georgia was found dead in his mansion near London less than two months after claiming he was the target of an assassination plot for helping lead a protest movement against his homeland’s government.

British police said Wednesday a major crimes unit was investigating the death late Tuesday of 52-year-old billionaire Badri Patarkatsishvili, which they were treating as suspicious pending an autopsy.

Patarkatsishvili built his fortune in Russia after the break-up of the Soviet Union through a partnership with Boris Berezovsky – another self-exile who is one of Russian President Vladimir Putin’s most vocal foes.

His death drew comparisons to the 2006 radiation poisoning in London of ex-Russian security agent Alexander Litvinenko. Moscow’s refusal to hand over the primary suspect, Andrei Lugovoi, has strained relations between Britain and Russia.

Police found no trace of radiation at the Georgian’s mansion, Britain’s Press Association reported, citing police sources.