A court in Moscow on Friday found prison doctor Dmitry Kratov not guilty of negligence causing Magnitsky's death.

Magnitsky blew the whistle on what he claimed was a scheme in which police investigators had stolen hundreds of millions of dollars from the state through fraudulent tax refunds. He was imprisoned on tax evasion charges.

The lawyer, whose family denounced the result as a sham, died in jail in 2009 after his pancreatitis went untreated.

An investigation by Russia's Presidential Council on Human Rights had found that Magnitsky was brutally beaten and denied medical treatment. The council accused the government of failing to prosecute those responsible.

Magnitsky's death has become a rallying point for human rights advocates around the world. US President Barack Obama this month signed a new law - the US Magnitsky Act - which imposes visa bans and freezes the US assets of Russian officials accused of involvement in the death of Magnitsky or other human rights violators.

Russian President Vladimir Putin responded to the law in his December 20 news conference saying the law was straining ties between Moscow and Washington: "This is very bad. This, of course, poisons our relationship," he said.

Moscow retaliated with a bill banning Americans from adopting Russian children. Putin, who signed the bill into law on Friday, said the move was a legitimate response to the US human rights sanctions.

Critics of the legislation say it would unfairly punish both Russian children and would-be American parents.

The law also blocks dozens of Russian children currently in the process of being adopted by American families from leaving the country. Over the past two decades more than 60,000 of them have been adopted by Americans.

hc/rc (Reuters, AP)