Russian oligarch Boris Berezovsky was a "broken man" after losing a multibillion-dollar court case to fellow Russian Roman Abramovich and regularly spoke of killing himself before his death, a British inquest heard.
Berezovsky's bodyguard Avi Navama said on Wednesday that his boss had asked him about the best ways to commit suicide and told him he was "the poorest man in the world" after losing a US$6 billion damages claim to his former partner in 2012.
Berezovsky (pictured), who became a Moscow powerbroker under the late President Boris Yeltsin only to fall foul of Vladimir Putin, was found dead a year ago in the bathroom of his former wife's home near Windsor, west of London, with a scarf around his neck.
Navama said the case against Abramovich triggered a change in Berezovsky's personality. He suffered from depression before his death at the age of 67.
"He told me he's not a billionaire, he's the poorest man in the world," Navama told the inquest at Windsor Guildhall.
A fast-talking former mathematician, Berezovsky scaled the heights of a ruthless post-Soviet business and political world, surviving years of power struggles and assassination attempts before fleeing to London in 2000 after a row with Putin.
Britain gave him political asylum in 2003 on the grounds that his life would be in danger if he went back, straining ties between London and Moscow.
He suffered a blow in 2011 when he was forced to pay one of Britain's biggest divorce settlements to former wife Galina and then lost a legal battle in London with Abramovich over shares in Russia's fourth-biggest oil company.
The inquest heard that in the months that followed, he began taking antidepressants and regularly talked about suicide.
Navama's wife Zoe Watson said in a witness statement that Berezovsky had become a different person and looked "a broken man". But his family said they believed he had been becoming more optimistic and suspect he was a victim of foul play.
Ex-wife Galina Besharova said in a witness statement that she was very suspicious of the idea that he killed himself.
The inquest heard there had been two plots to kill him, the first an assassination attempt by suspected Russian mafia in 1994 when a bomb exploded in his car, decapitating his driver.
The second alleged plot was in 2007 when London police warned of someone in the country planning to kill him and advised him to leave Britain.
Berezovsky was also friends with former Russian spy Alexander Litvinenko, who was murdered in London in 2006 with a radioactive isotope put in his tea.
The inquest heard that a device to monitor radiation levels carried by a paramedic who was the first on the scene of Berezovsky's death had sounded a warning tone while he was there.
But Detective Inspector Mark Bissell said tests by Britain's atomic weapons establishment had not found any radiation and that this had been ruled out.
"We believe Berezovsky took his own life," he said.
The inquest continues.