British police on Friday launched a murder probe into the death of Russian exile Nikolai Glushkov in London, after a post-mortem found he died from "compression to the neck".
"A murder investigation has been launched following the results of a post-mortem into the death of 68-year-old Russian businessman Nikolay Glushkov," London's Metropolitan Police said in a statement.
The retired Russian executive was found dead on Monday evening at his home in southwest London, where he had lived for two years.
"A special post-mortem began on Thursday, 15 March and we received the pathologist report today (Friday, 16 March), which gave the cause of death as compression to the neck," police said.
The Glushkov family's lawyer, Elena Tsirlina, told AFP they had been informed of the murder probe but would not be commenting on the case.
Glushkov had received political asylum in Britain after being jailed in Russia for money laundering and fraud.
He was linked to late Kremlin opponent Boris Berezovsky, an oligarch and one-time supporter of Russian President Vladimir Putin, who was found hanged in his home outside London in 2013.
The coroner's report proved inconclusive, but Berezovsky's death is now one of a number being re-examined by British authorities.
Police said the force's Counter Terrorism Command would continue to lead the investigation into Glushkov's death, "because of the associations Mr Glushkov is believed to have had".
The Russian embassy in London said this week that it had asked British authorities for details of Glushkov's death.
Britain's murder probe was launched shortly after Russia's Investigative Committee, which probes major crimes, announced its own investigation into the death of Glushkov.
The murder is not believed to be linked to the nerve agent attack on former double agent Sergei Skripal and his daughter Yulia in Salisbury, southwestern England, on March 4.
Both Britain and Russia have launched their own investigations into the poisoning, which has led to an ongoing diplomatic crisis.
London earlier this week announced a range of measures including the expulsion of 23 Russian diplomats, while Moscow has vehemently denied involvement in the attack and has vowed retaliatory moves.