In the wild world of Russian oligarchs, Boris Berezovsky, who has died aged 67, was among the wildest. He gloated over the semi-legal schemes that made him a billionaire in the 1990s and vowed to overthrow the Kremlin from exile in London.
Berezovsky, who fled to Britain in 2000 after a falling out with Russian leader Vladimir Putin, was found dead on Saturday at his home in Ascot, 40 kilometres west of London. Thames Valley police say his death was being treated as "unexplained" and there was no evidence of "third-party involvement".
He had survived one assassination attempt in 1995 in which a bomb decapitated his chauffeur, and openly expressed his fear that his life was in danger.
His friend and fellow Kremlin critic Alexander Litvinenko died from radioactive poisoning in London in 2006, in what Litvinenko's widow has said was an assassination by Russian agents.
Chemical and radiation experts searched his property but found no hazardous materials.
As speculation swirled over the cause of death, friends painted a picture of a man who had fallen on hard times.
One of Berezovsky's final acts was to wage an extraordinary legal battle in London in 2012 against fellow oligarch Roman Abramovich, which exposed the dirty secrets of Russia's big business in the post-Soviet years.
Berezovsky lost the suit and with it the reported hundreds of millions of dollars he spent on his legal team. He spent the final months of his life selling his old houses and even paintings, including a famous Andy Warhol print called Red Lenin.
"Berezovsky has been in a terrible state as of late," his lawyer Alexander Dobrovinsky told Russian state television. "He was in debt. He felt destroyed."
Putin's spokesman said Berezovsky had recently written to Putin saying he wanted to go home and asking "forgiveness for his mistakes". But Berezovsky's allies cast doubt on the report.
"I absolutely don't believe in this letter. This is not possible," opposition activist Andrei Sidelnikov told TV Rain.
"If there was such a letter, maybe Peskov distorted its meaning," Alexander Goldfarb, an activist and close associate of Berezovsky, told TV Rain.
"If it really exists, this letter deserves to be in a museum."
A journalist for Forbes Russia magazine, Ilya Zhegulev, also claimed Berezovsky had a change of heart towards Putin, telling Echo of Moscow radio statio Berezovsky praised the president's strong will in an off-the-record conversation on Friday.
Berezovsky also told Forbes Russia that his "life had lost meaning," a transcript on the magazine's website said.
The fast-talking and back-dealing Berezovsky's career traced the arc of Russian society from the dawn of free enterprise in the Soviet Union's dying days to the oligarch-dominated 1990s, followed by the return of state control in the new millenium.
When perestroika reforms in the late 1980s brought a modest tolerance for free enterprise, Berezovsky leapt at the opportunity, becoming a car dealer for state auto giant AvtoVAZ.
Within a matter of years, he was a multi-millionaire through what the government later alleged was a dirty scheme. He seized on the Western-style media obsession that flooded into the new Russia, building a news empire that included shares in two national TV networks and several respected newspapers.
His media might was key in 1996, when he banded a group of oligarchs together to lift Boris Yeltsin from single-digit approval ratings to victory in his re-election campaign against Communist Gennady Zyuganov in a matter of a few weeks.
In return, Yeltsin granted them huge swathes of national industries at a fraction of their value, ballooning their wealth and spawning a popular hatred among many Russians that endures to this day.
Berezovsky reaped political rewards as well. Yeltsin named him deputy head of the powerful Security Council and chief negotiator with Chechnya shortly after it had won independence.
He used his new political connections to expand into the lucrative energy business, and owned 80 per cent of oil company Sibneft by the late 1990s.
But his most significant political move was the one that inadvertently sealed his fate: helping Yeltsin choose Putin as Russia's second president.
Berezovsky quickly became a key target of Putin's crackdown on the oligarchs' political independence. He fled in November 2000 and fired back with his media arsenal, painting the president as a budding dictator.
In return, the state stripped him of his television holdings and tried for years to win his extradition from Britain - even after he won political asylum in 2003.
Prosecutors first charged he had defrauded the state of billions of dollars via his car dealing business. Graver accusations followed after he said in January 2006, that he was spending his billions on "preparing to take power by force in Russia," a threat he repeated in later years.
Additional reporting by Associated Press