In this task, you are given an article. Your task is to summarize the article in a sentence.
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Question: A police investigation has been launched into the death of the 67-year-old - a wanted man in Russia, and an opponent of President Vladimir Putin.
A former Kremlin power-broker whose fortunes declined under Mr Putin, Mr Berezovsky emigrated to the UK in 2000.
Thames Valley Police said the death, at a property in Ascot, Berkshire, was being treated as unexplained.
The area around the property has been cordoned off to allow the investigation to take place, the force said.
The inquiry was at a very early stage and more details will be released when available, it added.
A South Central Ambulance Service spokeswoman said it had been called to the property at 15:18 GMT.
"We sent a number of ambulance officers and an ambulance to the address. The 67-year-old male was confirmed deceased at the scene," she said.
Last year, Mr Berezovsky lost a Â£3bn ($4.7bn) damages claim against Chelsea Football Club owner Roman Abramovich.
Mr Berezovsky claimed he had been intimidated by Mr Abramovich into selling shares in Russian oil giant Sibneft for a "fraction of their true worth".
The allegations were completely rejected by the London Commercial Court judge, who called Mr Berezovsky an "inherently unreliable" witness.
By Steve RosenbergMoscow correspondent, BBC News
Russians have little sympathy for oligarchs, whether alive or dead.
That's because while Boris Berezovsky - and the tiny number of other tycoons - were striking rich in the 1990s, millions of people here were sliding into poverty.
As he gained in power, many Russians saw Berezovsky as the "grey cardinal" in the Kremlin - exerting huge political influence for his own benefit.
Having fled to London, he became a vocal Kremlin critic and pledged to work from self-imposed exile to depose President Putin. But back home in Russia,  many of Mr Putin's opponents blamed Berezovsky for having engineered the transfer of power from Yeltsin to Putin.
Boris Berezovsky will be remembered as a towering figure of the 1990s and as one of the most powerful men in Yeltsin's Russia.
BBC world affairs reporter Richard Galpin said sources have told him that Mr Berezovsky was depressed after the loss of the court case and was under financial pressure.
The tycoon's wealth is thought to have considerably diminished in recent years, leaving him struggling to pay debts in the wake of costly court cases.
Mr Berezovsky had made his fortune in the 1990s selling imported Mercedes as well as Russian-made cars.
He was one of the first Russian oligarchs - a tiny group of tycoons who at the end of communism used their connections to become rich almost overnight.
Later owning Sibneft, the national airline Aeroflot, and as primary shareholder in Russia's main television channel, he supported Boris Yeltsin's rise to power, enjoying huge influence during this era.
Mr Berezovsky survived numerous assassination attempts, including a bomb that decapitated his chauffeur.
During the later years of Yeltsin's presidency, Mr Berezovsky was part of the leader's inner circle as deputy secretary of Russia's security council.
"Boris Berezovsky was one of the most powerful men in Russia back in the 1990s," said the BBC's Moscow correspondent, Steve Rosenberg.
"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."
He then played a role in Mr Putin's rise in the late-1990s, before the new president moved to curb the political ambitions of Russia's oligarchs.
Leaving Russia for self-imposed exile in the UK, Mr Berezovsky became one of Mr Putin's fiercest critics.
But our correspondent said that on Saturday, a spokesman for Mr Putin said that Mr Berezovsky had sought the president's permission to return to Russia.

Answer: Exiled Russian tycoon Boris Berezovsky has been found dead at his home outside London.


Question: World number five Kvitova, 25, beat five-time Grand Slam winner Maria Sharapova 6-3 7-6 (7-3) in Saturday's second semi-final.
Earlier, Radwanska, 26, overcame Spain's world number three Garbine Muguruza 6-7 (5-7) 6-3 7-5.
It will be Radwanska's first final at the event in her seventh appearance.
The world number six made the decisive break in the 12th game of the third set to finally break the Spaniard's resistance.
"It was a great match from the beginning to the end, lots of ups and downs, so many rallies and a lot of running," Radwanska said.
Radwanska had taken a 3-0 lead in the first-set tie-break before eventually losing it 7-5.
"I didn't know I could come back after that first set -  I am just so glad I could win that match," she said.
In the second semi-final, Kvitova broke in the seventh and ninth games to take the first set against Sharapova, who had won all three of her round-robin ties despite arriving in Singapore after a long injury lay-off.
The world number four hit back to take a 5-1 lead in the second set, but 2011 champion Kvitova rediscovered her rhythm to claim the victory in straight sets.

Answer: Petra Kvitova of the Czech Republic will meet Poland's Agnieszka Radwanska in the final of the WTA Finals in Singapore on Sunday.


Question: The Russian coastguard is towing the ship towards the city of Murmansk, a journey expected to take several days.
Four of the Greenpeace activists had tried to board a Gazprom oil rig on Wednesday, to protest against drilling.
Russia accused Greenpeace of violating an exclusion zone around the rig, but the group said its ship was in international waters.
Greenpeace published photos that it said showed Russian security personnel in balaclavas confronting the activists with guns and knives after abseiling from helicopters onto the Dutch-flagged Arctic Sunrise.
Greenpeace says planned drilling at Gazprom's Prirazlomnaya rig in the Barents Sea threatens a unique and fragile environment - a claim denied by Moscow.
"The safety of our activists remains our top priority and we are working hard to establish what is facing them," said Ben Ayliffe, head of Greenpeace International's Arctic oil campaign.
"They have done nothing to warrant this level of aggression and have been entirely peaceful throughout," he said.
Greenpeace dismissed claims that a safety pod on the ship in any way resembled a bomb.
The group of activists being held includes six Britons.
A spokeswoman for the Murmansk region's border guards told local media that the Arctic Sunrise's captain had already been questioned, and the activists were being taken to court for "further legal procedures".
The Russian foreign ministry earlier accused the group of "aggressive and provocative" behaviour.
Moscow also said that its coastguard vessel had to fire warning shots across Arctic Sunrise.
The Gazprom project is Russia's first effort to extract oil from the Barents Sea.
Prirazlomnaya is scheduled to begin production by the end of the year. Russia's economy and its recent growth depend to a large extent on income from its huge oil and gas deposits.

Answer:
Greenpeace has called on Russia to release a ship seized in the Arctic with 30 activists on board.


