WINDSOR, England (Reuters) - Police believe foul play cannot be completely ruled out in the death of Russian oligarch Boris Berezovsky, whose body was found at the weekend with a piece of material around his neck, an inquest heard on Thursday.
Berezovsky, a sworn enemy of President Vladimir Putin, was found dead on Saturday in a luxury mansion in Ascot.
He survived years of intrigue, power struggles and assassination attempts in Russia, but had to flee to London in 2000 after a bitter row with the Kremlin leader.
Police have said there was no sign of a struggle and that the 67-year-old's death was "consistent with hanging", suggesting that he probably killed himself.
Asked however whether any third-party involvement was possible, Detective Inspector Mark Bissell told the inquest: "That cannot be completely eliminated." But he added that at this stage there was nothing to support that suspicion.
The inquest was adjourned to a date yet to be fixed and toxicology tests on the body, which was formally identified by Berezovsky's daughter Elizaveta, are still under way. Test results are likely to take several weeks.
Bissell said Berezovsky had been found with a "ligature" around his neck and a piece of similar material on the shower rail above him. He did not say what kind of material it was.
Berezovsky, who was last seen alive at around 10 on Friday, was the king-maker behind Putin's ascent to power in Russia, but later became his number-one enemy.
Britain gave him political asylum in 2003 on the grounds that his life would be in danger if he went back home.
His associates have hinted he was depressed after losing a $6 billion (4 billion pounds) court case last year against another Russian tycoon, Roman Abramovich, when a judge humiliated him publicly by saying he was an unimpressive and unreliable witness.
"He was depressed. He said so himself," said Alex Goldfarb, a friend of Berezovsky. "But it was under control. I was not worried about him in that respect."
Other people close to Berezovsky have said they are not convinced by the official account.
"In this past year of course he was depressed, but having known him for a long time, I can say he always had ups and downs and he was always capable of recovering, standing up and carrying on," said Andrei Sidelnikov, an opposition figure.
"He was such an optimistic man and none of his friends and associates can possibly believe that he committed suicide."
The coroner in charge of the inquest said he would allow a funeral to take place once he had enough information.
In Russia, state media quoted Deputy Prosecutor General Alexander Zvyagintsev as saying the government would continue efforts to "bring back assets that Berezovsky and his accomplices acquired criminally and legalised abroad".
A master of political manipulation, Berezovsky had been known as the "godfather of the Kremlin" and wielded immense influence for a decade after Soviet Union's collapse.
Once a mathematician with Nobel Prize aspirations, he built a vast business empire under former President Boris Yeltsin and was the first of Russia's so-called oligarchs.
He then became one of the first victims of a ruthless political crackdown of the early Putin era after falling out with his protégé.
Once in exile, Berezovsky often said he feared for his life, particularly after the fatal poisoning of his friend and former Russian spy Alexander Litvinenko with a dose of the radioactive isotope polonium-210 in London in 2006.
Another friend and business partner, Badri Patarkatsishvili, also died in unclear circumstances in Britain two years later.
For many, Berezovsky personified the decade of wild capitalism, chaos and violence that followed the Soviet fall. He left a trail of enemies in Russia and beyond.
Berezovsky survived an assassination attempt in 1994 when a bomb exploded in his car, decapitating his driver.
In his final months, he led a much less extravagant life, apparently bitter and broken and rarely seen in public.
He suffered another blow in 2011 when he was forced to pay one of Britain's biggest divorce settlements to his former wife Galina. Media reported that the settlement topped $100 million.
"My father was not the typical parent, nothing about him was ordinary," said his daughter Anastasia in a tribute. "He has coloured my life in infinite ways, and I know that what he concerned himself most with was making all his children proud."
Additional reporting by Steve Gutterman in Moscow; Editing by Alistair Lyon