Russian tycoon's mysterious death: Home to be sealed off for days Exiled Russian oligarch Boris Berezovsky, a prominent Russian opposition figure, was found dead at his home near London on Saturday. LONDON - A cordon will surround the U.K. home of exiled Russian tycoon Boris Berezovsky until at least Wednesday, while detectives await the initial results of autopsy into his unexplained death. The area will remained sealed off "until Wednesday or Thursday in order to protect the scene," a spokesman for Thames Valley Police said Monday. An earlier search for evidence of radiation or chemicals returned a negative result. Government pathologists were due to begin a post-mortem Monday afternoon on the 67-year-old, whose body was found in the locked bathroom of his large house in rural Berkshire, about 25 miles west of London. It was not clear when the initial results would be available to police. "It would be wrong to speculate on the cause of death until the post-mortem has been carried out," Detective Chief Inspector Kevin Brown said in a statement late Sunday. We do not have any evidence at this stage to suggest third-party involvement. However, his death has raised suspicion in Britain where memories linger of the murder of Berezovsky's friend, Alexander Litvinenko, a former Russian spy poisoned with radioactive material in London in 2006. Like Litvinenko, Berezovsky had become an enemy of Russia's president, Vladimir Putin and his suspicious death caused a major diplomatic rift between London and Moscow. 'Many enemies' His death on Saturday makes him the latest in a line of former Soviet residents to have met an untimely end in Britain. Litvinenko's wife, Marina, told the U.K."s Daily Telegraph that her friend Berezovsky had "many enemies" and that it was "not likely" he that he had committed suicide. Her lawyer last month accused Britain and Russia of colluding to try to shut down an inquiry into his death for the sake of lucrative trade deals. Matthew Lloyd / Getty Images The home of Russian oligarch Boris Berezovsky in Sunningdale, England. He orchestrated the re-election of Boris Yeltsin in 1996 and played a role in Putin's rise to prominence, but he fell out of favor with the latter after Putin became president of Russia in 2000. He suffered a huge financial blow in 2011 after agreeing one of Britain's biggest-ever divorce settlements - reportedly as much as $100m - with his former wife, Galina. Reuters reported that Berezovsky was also under pressure after losing a $6 billion court case to Chelsea Football Club owner Roman Abramovich, a former business partner he sued in one of the most expensive cases in British legal history. He had no money, he had lost it all. He was unbelievably depressed," Tim Bell, a public relations executive who was one of his closest British advisers, told the Sunday Times newspaper. It's all very sad. Meanwhile, Putin's spokesman said Berezovsky, seen by Moscow as a criminal who should stand trial for fraud and tax evasion, had written to Putin asking for forgiveness - a suggestion dismissed by one of the oligarch's friends, Reuters said. "Berezovsky sent Vladimir Putin a letter he wrote personally, in which he acknowledged that he had made many mistakes, asked Putin's forgiveness for these mistakes and appealed to Putin to help him return to his homeland," said Putin's spokesman Dmitry Peskov. A friend of Berezovsky's in London, Andrei Sidelnikov, told Reuters the idea that the businessman would write a letter to Putin was "complete nonsense." "He was a sane person and he understood that he would never be able to return under Putin's regime, for political reasons," Sidelnikov said. Full Russia coverage from NBC News This story was originally published on Mon Mar 25, 2013 7:19 AM EDT