An exiled Russian critic of Vladimir Putin was murdered by a Kremlin-backed assassin and British authorities know who did it, his friend claims.
Nikolai Glushkov, 68, was strangled with a dog lead at his home in New Malden, South West London, in March 2018 by a hitman who tried to make the attack look like suicide.
Yuli Dubov, the last surviving member of a group of Putin critics in the UK, says his friend knew his killer.
Mr Dubov, 73, spoke to the Mirror on the eve of the fourth anniversary of the unsolved murder as Scotland Yard conceded that it has exhausted all lines of inquiry.
He said: “All of the history of Nikolai’s communications with the outside world were on his laptop, his phone and his iPad.
“They have all been seized by the police and the man who killed Nikolai was certainly on them.
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“Nikolai let his killer into his house and there is no way he would have done that without communicating with him first.
“I think the British police and security services know who did it, they just haven’t got enough evidence. I believe that whoever was responsible is back in Russia and we will never see them leave the country.”
The killing happened a week after Russian spies poisoned Sergei Skripal and his daughter in Salisbury, Wilts.
Mr Glushkov, a former deputy director of Aeroflot, had previously told friends that he had been the target of an earlier poisoning attempt by two Russian men.
He was found by his daughter Natalia Glushkova and his partner Denis Trushin.
There was no sign of forced entry.
A toxicology report revealed that he had low levels of sedative drugs and alcohol in his system.
The pathology report found the injuries were consistent with a neck-hold, applied from behind or a “garroted sleeper hold”.
Coroner Chinyere Inyama last year recorded a verdict of unlawful killing.
Mr Dubov’s associates Boris Berezovsky, Alexander Litvinenko and Badri Patarkatsishvili also suffered untimely deaths.
He and Berezovsky were granted asylum in Britain in 2003, a decision that infuriated the Kremlin. Mr Dubov said of the invasion: “The sanctions are working but should have been introduced 15 years ago.
“Putin didn’t have these new rockets, he didn’t have this huge army. Now it’s too late.”
Scotland Yard say Counter Terrorism detectives continue to investigate the murder.
