Russian businessman Nikolai Glushkov, who was found dead in 2018, was strangled in his home in southwest London by an unidentified person, a British coroner has ruled, the BBC reported.
Glushkov fled Russia after being accused of fraud during his time as deputy director of the Aeroflot airline, and was granted political asylum in the UK in 2010, the BBC reported on Saturday.
Senior coroner Chinyere Inyama ruled that Glushkov was unlawfully killed.
A pathology report summarised to the court said the injuries "could be consistent with a neck-hold, applied from behind, and the assailant being behind the victim," the BBC reported.
British police have appealed for information as part of a murder investigation and said they were seeking to trace a black car that was seen around his home but which has never been traced.
"This has been a hugely complex, challenging investigation from the outset," said Commander Richard Smith, head of London police's Counter Terrorism Command.
"Officers have taken hundreds of statements and collected a large amount of evidential material, but so far no arrests have been made," he said in a police statement on Friday.
Counter terrorism police are heading the inquiry into the death. It occurred shortly after the attempted murders of former Russian spy Sergei Skripal and his daughter in the English city of Salisbury, although detectives said there was nothing to link the events.
Glushkov was also an associate of late Russian tycoon Boris Berezovsky, who was found dead in March 2013 with a scarf tied around his neck in the bathroom of a luxury mansion west of London.
His family feared he might have been murdered by enemies from Russia. British police and forensic experts concluded it was suicide, although a British judge in 2014 reached an open verdict on Berezovsky's death, saying he could not be sure if the Russian killed himself or was the victim of foul play.