A post-mortem examination on the body of exiled Russian oligarch and Kremlin critic Boris Berezovsky has found the cause of death to be "consistent with hanging", British police said.
The findings of a pathologist said there was no sign of a violent struggle.
Detectives are focusing on 67-year-old tycoon's state of mind in the final days of his life.
His have said he had been deeply depressed in recent weeks and was left distraught by his defeat last year in a multi-million-pound court battle with Roman Abramovich, another Britain-based Russian oligarch who owns English Premier League football club Chelsea.
Berezovsky's body was found in his locked bathroom at his mansion in Ascot, an upmarket town to the west of London, on Saturday.
A bodyguard broke down the door and discovered the body on the bathroom floor after becoming concerned that he had not seen his boss for several hours.
"The results of the post-mortem examination, carried out by a Home Office pathologist, have found the cause of death is consistent with hanging," a police statement said Monday.
"The pathologist has found nothing to indicate a violent struggle."
Unconfirmed reports said a scarf had been found next to the body.
Toxicology tests will also be carried out, but the results will not be known for several weeks, police said.
Berezovsky's friend and fellow Kremlin critic Alexander Litvinenko was killed by radioactive poisoning in London in 2006 and Litvinenko's widow maintains his death was ordered by Moscow.
Reports said samples from the tests carried out on Berezovsky will be sent to Britain's Atomic Weapons Establishment, which discovered the presence of the radioactive substance Polonium 210 in Litvinenko's body.
Police officers trained in detecting chemical, biological, radiological and nuclear material inspected Berezovsky's house as a precautionary measure after his body was discovered, but they gave it the all-clear.
Many of Berezovsky's friends remarked on his depressed demeanour recently. A journalist from Forbes magazine who interviewed him last week said the fallen oligarch complained that "life had lost meaning".
But Russian media -- which had published comments pointing to a variety of conspiracy theories ranging from assassination to a fake death -- appeared to retain a degree of scepticism towards an eventual conclusion of suicide by hanging.
The state news agency RIA Novosti said the initial conclusions about the circumstances of the death had "not brought clarity but raised even more questions" and noted that British police had published no information about how precisely Berezovsky may have hanged himself.
Friends said Berezovsky was left distraught and under financial strain by his court defeat against Abramovich, his former protege, in August, and by the break-up of his latest relationship.
Berezovsky sued Abramovich over an oil deal, but the judge in the case in London described Berezovsky as "an unimpressive, and inherently unreliable, witness".
A wounded Berezovsky said he had the impression that Russian President Vladimir Putin "himself wrote this judgement".
The legal bills for the case could reach £100 million ($118 million, 150 million euros).
But despite his apparent depression, Berezovsky's fellow British-based Russian exile, the former Chechen rebel Akhmed Zakayev, said he had doubts about a suicide.
"I do not think that things were so bad with him that he would end his life by suicide," Zakayev told BBC Russian.
Berezovsky was a former academic who became an integral part of the inner circle of former Russian president Boris Yeltsin. He was one of a handful of businessmen who became billionaires following the rapid privatisation of Russian state assets in the 1990s.
He helped to promote Putin as Yeltsin's successor, but later fell out with him as Putin turned against the oligarchs.
Berezovsky fled Russia in 2000, just in time to escape arrest on fraud charges.
He used Britain as a springboard to criticise the Kremlin and gave financial support to a circle of exiled Russian critics that included Litvinenko.
Adding to the intrigue, Putin's spokesman claims Berezovsky had recently sent a letter to the president asking to be allowed to return to Russia.