A Russian lawyer who was left to die in jail after claiming that police stole $230 million might have taken the money himself, Russian authorities said Monday, citing new testimony. Supporters scoffed at the claim.

The case of Sergei Magnitsky — who died last year at age 37 when the pacreatitis he developed in jail was left untreated — is being scrutinized as a barometer of President Dmitry Medvedev's commitment to the rule of law and also of investment-hungry Russia's true openness to foreign capital.

The announcement, made on the eve of the first anniversary of Magnitsky's death, was ridiculed by others linked to the case.

The accusations are "complete nonsense and total fabrication made by people in the Interior Ministry who participated in the crime and tortured and murdered Sergei Magnitsky," investor William Browder told The Associated Press from London.

"Sergei was not only innocent, but he was the person who discovered the crime and who was courageous enough to testify about it," he added.

Legislators in the U.S. and Britain are seeing a documentary film on Tuesday made by Magnitsky's supporters, who hope to ramp up the pressure on Russian authorities to prosecute those responsible for his death and punish the officials they allege defrauded the state.

Magnitsky had been charged with tax evasion linked to his defense of Hermitage Capital Management, a multibillion-dollar fund headed by Browder, who has since been deported from Russia as a national security threat.

Hermitage accuses Interior Ministry officers of seizing ownership documents of three of its subsidiaries in 2007, then using those documents to register their own people as owners and directors. They then filed a tax claim, saying they made a much smaller profit than originally described and asked for a tax return, according to Hermitage.

The total return for the three was 5.4 billion rubles ($230 million at the time).

But Interior Ministry spokeswoman Irina Dudukina said Monday that one suspected accomplice had been arrested and implicated Magnitsky in a scheme to steal the money by illegally filing tax reclaim forms. Another man who has been convicted of fraud in the case also testified against Magnitsky.

But Dudukina added that these testimonies "have yet to be verified."

Browder said he used Magnitsky's findings to warn the Prosecutor General's office of the impending theft but Dudukina insisted the Interior Ministry had not received any warnings from Hermitage.

Browder noted that the two men who accuse Magnitsky of perpetrating the fraud had been previously convicted of murder and burglaries.

Magnitsky originally testified against Interior Ministry officers Pavel Karpov and Artyom Kuznetsov, accusing them of stealing the money before the same officers initiated proceedings against him. No action has been taken against the officers, some of whom last week received state awards for their work.

Medvedev fired several top prison officials over Magnitsky's death and has pledged a full investigation. No one has been prosecuted in the prison death.

U.S. Sen. Benjamin Cardin, a Democrat from Maryland, in April urged the U.S. State Department to impose a travel ban on 60 Russians who are believed to be involved in Magnitsky's persecution in jail and the fraud he uncovered.

Dudukina, however, said the Cardin list aims to obstruct Russian investigators from uncovering crimes abroad.