The police sealed off the British home of exiled Russian oligarch and Kremlin critic Boris Berezovsky on Sunday and sent in hazardous material experts following the discovery of his body at the house.
The 67-year-old was found dead in his mansion in the well-heeled commuter town of Ascot, near London, on Saturday afternoon.
His lawyer Alexander Dobrovinsky said his death may have been suicide brought on by depression over his debts.
But since the tycoon survived one assassination attempt in 1995 and remained fearful of other bids to kill him, his death is bound to provoke speculation.
The police shut down the streets surrounding the gated property overnight and sent in chemical, biological, radiological and nuclear (CBRN) experts to investigate what they described as an “unexplained” death.
Berezovsky’s friend and fellow Kremlin critic Alexander Litvinenko was killed by radioactive poisoning in London in 2006, in what his widow has said was an assassination by Russian agents.
“Specially trained officers are currently at the scene, including CBRN officers, who are conducting a number of searches as a precaution,” a police statement said.