A Russian man who was associated with a leading critic of Vladimir Putin has been found dead at his London home.
The cause of Nikolai Glushkovs death was not immediately known and police have not yet confirmed whether they are investigating.
The 68-year-old was a close friend of exiled Russian oligarch Boris Berezovsky, who was himself a friend of murdered spy Alexander Litvinenko.
Mr Berezovsky was found hanged in the bathroom of his Berkshire home in 2013.
Police said a post-mortem showed no sign of a violent struggle, and an inquest recorded an open verdict after hearing conflicting evidence.
His death is among up to 14 being reviewed by police and MI5 in light of the nerve agent attack on Sergei Skripal and his daughter in Salisbury.
Friends of Mr Glushkov were posting news of his death on social media, while his lawyer confirmed his passing to Russia’s Business FM radio station.
He served a five-year term for money laundering and fraud in Russia, then fled the country after being handed a two year suspended-sentence for fraud in 2006.
Last year, he was sentenced to eight years imprisonment and a million-Ruble fine in absentia for allegedly defrauding Aeroflot.
Mr Glushkov worked as the First Deputy General Director for Russias flag carrier in the late 1990s, having worked for Mr Berezovskys LogoVAZ car company.
His LinkedIn page listed him as a private consultant in financial services since 2011.