Acquittal over lawyer Magnitsky death in Russian jail 28 December 2012 Last updated at 09:51 A Moscow court has acquitted a prison doctor accused of negligence over the death of anti-corruption lawyer Sergei Magnitsky. The judge said Dmitry Kratov had acted appropriately when Magnitsky fell ill in jail in 2009. Mr Kratov was deputy head of Butyrka prison at the time. The case is at the centre of a recent souring in Russian-US relations. Russian President Vladimir Putin has now signed into law a ban on Americans adopting Russian children. A Russian official report last year concluded that Magnitsky had been tortured and handcuffed in jail. Magnitsky represented London-based Hermitage Capital Management (HCM). He uncovered what he described as a web of corruption involving Russian tax officials, including the alleged theft of more than $200m (£125m). After reporting it to the authorities, he was himself detained on suspicion of aiding tax evasion, and died in custody on 16 November 2009 at the age of 37. His case became a symbol of the fight against corruption in Russia. Mr Kratov is the only Russian official to have gone on trial in the high-profile case. Earlier this month the US Congress adopted the Magnitsky Act, which blacklists Russian officials accused of human rights abuses. Russia retaliated by banning adoptions of Russian orphans by Americans. On Friday, Russian President Vladimir Putin signed that adoption ban into law. It had already been approved by the Russian parliament. "I see no reason not to sign it," Mr Putin told officials earlier, at a televised meeting. He said he would also sign a presidential decree "that will modify the support mechanisms for orphaned children." The Moscow judge on Friday ruled that Mr Kratov had organised Magnitsky's transfer to hospital and had "taken all the necessary measures to treat the illnesses" that Magnitsky was suffering from. Magnitsky had pancreatitis, but an investigation by Russia's presidential council on human rights concluded that he had been severely beaten and denied medical treatment. Magnitsky's mother, widow and lawyers believe that Mr Kratov has been used as a decoy by the authorities to protect the real culprits in the lawyer's death. Mr Kratov's assistant Larisa Litvinova had also been a suspect in the case, but the investigation into her actions was dropped in April.