Thames Valley Police said Monday that further tests, including toxicology examinations, will be carried out. The force did not specify whether the 67-year-old businessman hanged himself, but they have said there was no evidence to suggest anyone else was involved in the death.
Once one of Russia's richest men and a Kremlin powerbroker, Berezovsky fled to Britain in 2001 and claimed political asylum after a bitter falling out with Russian President Vladimir Putin. He became a vocal critic of the Kremlin.
Berezovsky had survived several assassination attempts in Britain and Russia, including a car bomb in 1994 that killed his driver.
Berezovsky's body was found by an employee on the bathroom floor at his upscale England home on Saturday. The employee called an ambulance after he forced open the bathroom door, which was locked from the inside. Police said the employee was the only person in the house when Berezovsky's body was discovered.
A forensic examination of Berezovsky's home will continue for several days, police said Monday.
A mathematician-turned-Mercedes dealer, Berezovsky built up his wealth during Russia's chaotic privatization of state assets in the 1990s following the breakup of the Soviet Union. In return for backing Russian President Boris Yeltsin, he gained political clout and opportunities to buy state assets like oil and gas at knockdown prices.
Berezovsky helped build Putin's power base but fell out of favour when the new president moved to curb the ambitions of the oligarchs. The tycoon was charged in Russia with fraud and embezzlement.
Berezovsky later associated himself with ex-KGB agent Alexander Litvinenko, another Kremlin critic. Litvinenko died after ingesting polonium in his tea at a London hotel in 2006.
In recent years, Berezovsky's fortunes declined with numerous expensive court cases.
Last year, Berezovsky lost a huge legal battle against former business partner and fellow Russian tycoon Roman Abramovich, which left him with legal bills of at least 35 million pounds ($53.3 million.)
Berezovsky had said that Abramovich, the billionaire owner of Chelsea Football Club, cheated him out of his stakes in the oil group Sibneft, arguing that he blackmailed him into selling the stakes vastly beneath their true worth after he fell out of Putin's favour.
But a judge threw out the case in August, ruling that Berezovsky was a dishonest and unreliable witness, and rejected Berezovsky's claims that he was threatened by Putin and Alexander Voloshin, a Putin ally, to coerce him to sell his Sibneft stake.
In 2010 Berezovsky also took a hit with his divorce from Galina Besharova, paying a settlement estimated to be as high as 100 million pounds.