Police in Britain have searched the home of Russian tycoon Boris Berezovsky for chemical, biological and nuclear material and given it the all-clear.
Mr Berezovsky, who was 67, was found dead on Sunday and police are treating his death as unexplained.
He emigrated to Britain after falling out with Russia's President Vladimir Putin and was granted asylum in 2003 on the grounds his life would be in danger in Russia.
He amassed a fortune in the 1990s after the privatisation of state assets following the collapse of Soviet communism.
Mr Berezovsky survived numerous assassination attempts, including a bomb that decapitated his chauffeur.