British police investigating the death of exiled Russian oligarch and Kremlin critic Boris Berezovsky said on Sunday that a search of his house by chemical, biological and nuclear experts had found "nothing of concern".

The 67-year-old exile, who emigrated to Britain in 2000 after falling out with President Vladimir Putin, was found dead in his mansion in the upmarket town of Ascot outside London on Saturday.

Police officers trained in detecting chemical, biological, radiological and nuclear (known as CBRN) material inspected the house as a precautionary measure but have given it the all clear.

"I am pleased to say the CBRN officers found nothing of concern in the property and we are now progressing the investigation as normal," Police Superintendent Simon Bowden said.

Police are treating his death as "unexplained".

Berezovsky survived one assassination attempt in 1995 in which a bomb decapitated his chauffeur, and he openly expressed his fear that his life was in danger.

His friend and fellow Kremlin critic Alexander Litvinenko died an agonizing death from radioactive poisoning in London in 2006.

Berezovsky's wealth had diminished in recent years, and last year he lost a bitter multimillion pound legal battle with fellow British-based oligarch Roman Abramovich, the owner of Chelsea Football Club.

Berezovsky had sought more than 3.1 billion pounds ($4.75 billion) in damages and accused Abramovich of blackmail, breach of trust and breach of contract in an oil deal.

Following his defeat in a London court, he was forced to agree to pay Abramovich 35 million pounds in legal costs, although there is speculation that the final bill will be far greater.

The judge in the case described Berezovsky as "an unimpressive and inherently unreliable witness".

Yeltsin's confidante

Berezovsky was a close confidante of former Russian president Boris Yeltsin and one of a handful of businessmen who became billionaires following the privatization of Russian state assets in the 1990s.

But he fell out with Yeltsin's successor, Putin, and fled Russia in 2000 just in time to escape arrest on fraud charges.

In London, Berezovsky became one of the Kremlin's most outspoken critics and is believed to have given financial support to a circle of exiled Russian critics that included Litvinenko.

Berezovsky's body was found by a bodyguard at his property. Paramedics were called to the house at 3:18 pm, but he was pronounced dead at the scene, the ambulance service said.

Unconfirmed reports say he was found in a bath.

The tycoon's friend Demyan Kudryavtsev dismissed speculation that Berezovsky had killed himself.

"There are no external signs of a suicide," he told the Prime News Agency in Russia.

"There are no signs that he injected himself or swallowed any pills. No one knows why his heart stopped."

Private life

Berezovsky's private life had also been turbulent in recent years. His divorce with second wife Galina Besharova in 2011 was dubbed one of the costliest in Britain, and there had been a more recent legal wrangle with his partner Elena Gorbunova.

Born on Jan 23, 1946, in Moscow, Berezovsky worked as an academic for nearly two decades before taking advantage of the perestroika reforms to make his fortune.

However, the fast-talking man with a taste for the high life fell foul of Putin's crackdown on the oligarchs' political independence. In 2003, Britain granted him political asylum.

After news of Berezovsky's death emerged, Kremlin spokesman Dmitry Peskov said the oligarch had written to Putin a couple of months ago saying he wanted to go home.

"He asked Putin for forgiveness for his mistakes and asked him to obtain the opportunity to return to the motherland," Peskov said.

AFP-AP

(China Daily 03/25/2013 page11)