The lawyer for a Russian millionaire who mysteriously died in England after helping expose an alleged Russian money laundering scheme urged an inquest Friday not to dismiss the possibility his client was poisoned.
Alexander Perepilichny, 44, collapsed in November 2012 while jogging near his mansion in the southeastern county of Surrey.
An investigation by Surrey Police found he died of natural causes but there have also been suspicions he was murdered following orders from Russian President Vladimir Putin.
Perepilichny moved to Britain in 2009 and helped arch-critic of the Kremlin, investor Bill Browder, document allegations that $230 million (195 million euros) was stolen from his Hermitage Capital hedge fund by Russian officials.
Browder has said that Perepilichny provided "lock-tight documentary evidence" in the case.
On the last day of the inquest, London's High Court heard how the businessman appeared on a "hit list" in Moscow and had applied for additional life insurance before his death.
He had also just finished fighting off a legal challenge, allegedly spearheaded by one of the two Russians that Britain believes poisoned former spy Alexander Litvinenko with a radioactive substance in London in 2006.
The coroner leading the inquest ruled on Tuesday that material that could reveal whether Perepilichny was also working with British spies could not be revealed for national security reasons.
The secrecy application was lodged by British interior minister Sajid Javid.
Extensive tests have failed to identity any poison in Perepilichny's body. Police believe he died from "sudden adult death syndrome" (SADs).
But the lawyer representing Perepilichny urged the coroner not to "brush away" the possibility that he was poisoned with an agent used by Russia that could be hard to identify.
"It is not a fanciful proposal that people might come from Russia with a view to harm someone they saw as the enemy," lawyer Bob Moxon said.
A lawyer representing Hermitage Capital added that "at least 10 poisons" remain possible culprits.
Media reports in 2017 said US intelligence also believed Perepilichny was likely "assassinated on direct orders from Putin or people close to him".
- Police reject murder claims -
A representative for Surrey Police insisted on Friday that "there is insufficient evidence to support unlawful killing".
The result of the coroner's probe -- formally called an inquest in Britain -- provide the legal grounds for a possible criminal inquiry.
The original fraud at Hermitage Capital was flagged by Moscow tax accountant and lawyer Sergei Magnitsky, who specialised in solving financial crimes.
Magnitsky was quickly jailed in Russia on what were widely considered trumped up charges and died in pretrial detention.
His case sparked an international scandal that saw the US and EU along with some other Western governments blacklist Russian officials and freeze their financial assets.
Browder attended Friday's final day of the inquest, which has lasted over a year.