By Maria Golovnina
LONDON (Reuters) - British police have carried out toxicology tests on the body of a Russian anti-corruption whistleblower whose mysterious death in England has put a new spotlight on Russian criminal groups entrenched in Europe.
Alexander Perepilichny, 44, moved to Britain three years ago and had been helping Swiss prosecutors uncover a shady Russian criminal group suspected of being involved in large-scale, cross-border tax fraud violations.
Police have struggled to establish the cause of his death since he suddenly collapsed and died near his home on an up market, heavily protected estate in Surrey, south of London, on November 10.
Following an inconclusive post-mortem on November 14, investigators conducted another examination of Perepilichny's body as well as toxicology tests.
"Toxicology tests are being carried out as part of the investigation," a Surrey police spokeswoman said on Friday, adding that it could take months to get the results.
"The death is being treated as unexplained and remains under investigation."
Although toxicology tests are often standard practice following inconclusive post-mortem examinations, the move has evoked memories of the 2006 death of former Russian spy Alexander Litvinenko who died in London after drinking tea poisoned with radioactive polonium-210.
Perepilichny's case has shed new light on a multimillion-dollar tax fraud scheme that was originally uncovered by Russian lawyer Sergei Magnitsky, who was jailed in 2008 by the Russian authorities on charges his colleagues say were fabricated.
In 2009, Magnitsky died in a Russian prison, provoking an international outcry and becoming a symbol of human rights abuse and corruption in Russia.
Perepilichny is the fourth person linked to the case to have died in unusual circumstances.
In 2010, he came forward with information linking Russian government officials to a tax fraud scheme involving a Swiss bank, a move that helped Swiss prosecutors open a far-reaching criminal investigation in 2011.
Britain is the chosen home for many Russians, some seeking employment opportunities or refuge from political persecution. But there are also fears that London is turning into a playground for Russian mobsters trying to avenge their former partners hiding abroad.
Russian officials have played down Perepilichny's link to the Magnitsky affair, which has strained Moscow's relations with the West and prompted the United States to push for a bill cracking down on Russian corruption.
"We cannot see any connection between the death of Mr. Alexander Perepilichny, the causes of which are yet to be established, and the so called 'Magnitsky case,'" the Russian embassy in London said in a statement.
Britain's Independent newspaper, financially backed by a Russian billionaire critical of the Kremlin, reported on Friday that Perepilichny received a warning a year ago that his name was on a hit list in Russia.
"It was like an order book," a source described as an acquaintance of Perepilichny told the paper.
"His name was in it."
(Writing by Maria Golovnina; editing by Andrew Roche)