Boris Berezovsky, the used-car salesman who became a major influence on Boris Yeltsin in shaping post-Soviet Russia has died at the age of 67. London officials are describing his death as "unexplained." Theories of his death now range from suicide, to a heart attack, to murder, as British authorities cordon off his property.

Berezovsky, who was living outside of London and had reached apparent financial ruin, was a wanted man inside of his native Russia for "economic crimes." He clashed frequently with Russian strongman President Vladimir Putin after assuming a massive amount of wealth during the rash of privatizations that swept Russia in the 1990s. In 1997, Forbes estimated that he was worth $3 billion.

Recently however, Berezovsky had become involved in a series of high-profile and highly-embarrassing court cases, including losing a $4.7 billion claim against fellow oligarch Roman Abramovich.

Berezovsky made his fortune by selling used Mercedes to a newly-wealthy Russian luxury class, and was a main supporter of the rise of Boris Yeltsin in shaping Russian Federation policy. The BBC reports that, "Mr Berezovsky survived numerous assassination attempts, including a bomb that decapitated his chauffeur."

Berezovsky also supported President Putin's rise to power, but soon became one of his fiercest critics as Putin moved to curb the influence of Russia's oligarch class. Berezovsky moved to London voluntarily, only to find himself in virtual exile after Russian courts found him guilty of economic crimes in absentia. Russia repeatedly tried to extradite Berezovsky from the UK, but he was granted political asylum there in 2003.

"He rose from being a mathematician, a computer programmer and a used car salesman, to being such an influential figure in Boris Yeltsin's Russia," said the BBC's Moscow correspondent Steve Rosenberg.

Berezovsky had recently been trying to sell off personal assets to deal with his enormous debt and outstanding legal fees. Friends reported that Berezovsky had recently been depressed.

"It was as if life had already left him," Mikhail Kozyrev, a journalist, told Moscow's TV Rain.