Britain's High Court on Monday threw out a libel suit by a former Russian interior ministry investigator over accusations that he was involved in the death of whistleblowing lawyer Sergei Magnitsky.
Pavel Karpov is named on a US blacklist of Russians involved in the case of Magnitsky, who died in jail in 2009 after being detained while investigating a massive theft of state assets by Russian officials.
The ex-policeman had sought to sue Magnitsky's former boss, William Browder, the US-born British chief executive of the Hermitage Capital investment fund, which was the focus of the alleged embezzlement scam.
Hermitage Capital and US lawyer Jamison Reed Firestone, who hired Magnitsky as an auditor in his Moscow office, were also named in the libel suit, which centred on a number of videos posted online about the Magnitsky case three years ago.
But judge Peregrine Simon said in a written ruling: "I have concluded that these proceedings should be struck out as abuse of the process and/or under the inherent jurisdiction."
The judge said that Karpov had failed to establish that he had a reputation in England and Wales that could be damaged by the allegations in the video, a requirement in libel cases.
He said the Russian had tried to bring similar proceedings in his home country, "the natural forum for such a claim", which had been unsuccessful.
And he noted that any success in the libel suit "would be unlikely to assist (let alone achieve) the most important of the Claimant's stated objectives: his removal from the Magnitsky list".
But the judge said Karpov had achieved "a measure of vindication as a result of the views I have expressed on his application", namely that Browder and his campaign were not in a position to justify their allegations that Karpov caused, or was party to, the torture and death of Magnitsky.
A spokesman for Hermitage Capital welcomed the ruling, which it said was an attempt to use Britain's tough libel laws to stifle a campaign to get justice for Magnitsky.
"Thankfully, the court took a decision which reflects natural justice and common sense," he said.
Karpov retired as a policeman in July 2012, having spent the previous three years working for the Investigation Committee of the interior ministry. The committee named him 'best investigator' in 2010.
Magnitsky had accused Karpov and others of illegally gaining control of subsidiaries of Hermitage Capital and using them to fraudulently reclaim billions of rubles.
Karpov was later appointed to the team bringing a tax evasion case against the lawyer, who was in pre-trial detention when he died of untreated illnesses on November 16, 2009, aged 37.