Russia will not receive legal assistance from Switzerland in its continuing probe into the Russian oil giant, Yukos, said the Swiss Federal Court on Monday.
It froze SFr6.2 billion ($4.9 billion) linked to Yukos in 2004 at the request of Russia. A large part since has been released, but almost $50 million remain blocked.
In three rulings, Switzerland's highest court partly accepted appeals by a number of companies that were opposed to handing over financial information as part of the investigation into Yukos.
Judges also called on the Swiss Federal Prosecutor's Office to seek more clarification from the Russian authorities on the case.
The remaining accounts linked to the case, said to contain $48 million, will remain frozen.
The court also wants the Federal Prosecutor's Office to acquire more legal documents from Russia and have them translated, so it can continue looking into the affair.
Switzerland has been involved in the Yukos probe since March 2004 when it blocked the bank accounts, which Russia suspects hold money from deals involving illegal fertiliser, oil and oil products.
But a few months later the Federal Court ordered the Swiss authorities to free several billion of these assets, following appeals by lawyers representing Mikhail Khodorkovsky, the former head of Yukos, and Menatep Holding, which controlled the group.
Khodorkovsky, once Russia's richest man, has since been convicted of tax evasion and fraud and was sent to a Siberian jail in October 2005 to serve his eight-year jail sentence.
In July last year the Swiss Federal Court decided to hand over 80 files of information – from the 1,300 files it has – to the Russians, following a series of requests for legal assistance.
In the latest rulings, Swiss judges said the Yukos case was not only very complex, but also dealt with huge sums of money.
They also found gaps and insufficiencies in the up to 20 Russian requests for legal assistance, it was revealed.
The Swiss authorities could not ignore the Council of Europe's reservations over the trials of Khodorkovsky and an associate, Platon Lebedev, a statement said.
This combination of circumstances had led the Swiss authorities to "depart exceptionally from its habitual reserve" during such a case.
The Federal Court reserved some criticism for the way the Russian authorities had handled their investigation, including a "campaign of intimidation" against several parties.
Judges also questioned the purpose of Russia continuing the investigation if convictions had already been handed out.
Khodorkovsky built up a multi-billion dollar fortune before falling from grace.
Critics accuse him of plundering Russia's natural wealth for his personal gain. But supporters say he has done nothing wrong and is being punished for funding opposition political parties.
Khodorkovsky is expected to appeal against the ruling before Russia's Supreme Court, as well as take the case to the European Court of Human Rights.
swissinfo with agencies
The Swiss Federal Court is Switzerland's supreme court.
Appeals against cantonal verdicts can end up in the Federal Court.
Criminal and civil law are federal matters; but organisation and procedures are in the hands of cantonal courts.
The Federal Court also checks the decisions coming from cantonal and federal authorities.
In March 2004, the Swiss authorities blocked SFr6.2 billion, said to be put into Swiss accounts by Yukos management.
In June 2004, a large part of these assets were unfrozen during the course of an investigation into the Yukos affair.
On Monday the Swiss Federal Court rejected a new request for judicial assistance by Russia. This concerned the remaining funds still blocked in Swiss accounts.
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