MOSCOW (Reuters) - Europe’s top human rights court rebuked Russia on Tuesday for multiple violations of the basic rights of lawyer Sergei Magnitsky who died in a Moscow prison in 2009 after complaining of mistreatment.

FILE PHOTO: Flowers lie near the grave of lawyer Sergei Magnitsky in the Preobrazhensky cemetery in Moscow March 11, 2013. REUTERS/Mikhail Voskresensky/File Photo

Magnitsky, whose death became a cause celebre, received inadequate medical care in custody which led to his death, was ill-treated by prison guards and was held in over-crowded conditions, the European Court of Human Rights ruled.

The court said the subsequent investigation into his death had been lacking, and ordered Russia to pay out 34,000 euros ($38,000) to Magnitsky’s widow and mother who took up his case at the court in Strasbourg after he died.

The court rejected a complaint calling his arrest and detention ill-founded and said that authorities had reasonable grounds to suspect him of being involved in tax evasion.

That suspicion, however, should not have been grounds to keep him in custody for more than a year, the court said, adding that it had been “inherently unfair” to continue proceedings after his death.

Russia’s Justice Ministry said it was studying the ruling and would decide whether or not to appeal against it in the next three months, Interfax news agency reported.

Magnitsky died in pre-trial detention in November 2009, having been charged with organizing tax evasion. Russia later convicted him posthumously.

Bill Browder, an investment fund manager who employed Magnitsky, led a campaign to expose corruption and punish Russian officials whom he blames for Magnitsky’s death.

Russian prosecutors have said they suspected Browder of ordering a string of murders, including of Magnitsky, in a twist the financier dismissed as ludicrous.

The United States passed a law known as the Magnitsky Act in 2012 under which it has imposed visa bans and asset freezes on Russian officials linked to the lawyer’s death. Similar legislation has been passed in other European capitals.

Browder on Tuesday said the European Court ruling was a “resounding victory” that “completely destroys the lies and propaganda about Sergei Magnitsky”.

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