"Magnitsky was an economist and worked as an accountant and auditor. In this capacity he devised tax evasion schemes," police spokesperson Irina Dudukina said at a press conference on Monday that marked the first anniversary of the lawyer's death.

Investigators said on Monday they had recovered 15 percent of the $175.29 million Magnitsky allegedly helped Hermitage Capital CEO William Bowder to siphon off from public funds.

Magnitsky claimed he had been jailed on fabricated evidence in a bid to hush up his testimony against two investigators, Artyom Kuznetsov and Pavel Karpov, in which he accused them of defrauding the state of $230 million.

Magnitsky was reported to have been subjected to torture in a bid to force him into withdrawing his allegations against the officers.

But the Interior Ministry today denied corruption charges against Kuznetsov and Karpov, which were brought by UK Lawyer Jamison Firestone after Magnitsky's testimony.

Meanwhile, Hermitage Capital CEO Bowder said on Monday he would not pay off an alleged tax debt of $16 million.

Investigators had previously said they would drop charges against Bowder, who was banned from Russia in 2005, if he agreed to pay off the debt voluntarily.

Magnitsky was kept in the cramped 8.2 sq m cell with two others without trial for almost a year before he died. Browder said Magnitsky was "killed" after refusing to sign a confession admitting his role in the company's alleged tax scam.

The death provoked uproar both in Russia and abroad, with President Dmitry Medvedev calling for a full investigation into the case. Earlier this year, the president pushed through a law allowing suspects in economic crimes to be released on bail.

A probe into Magnitsky's death has been prolonged until February 2011, lawyer Yelena Oreshnikova told RIA Novosti on Monday.

Sergei Magnitsky /Jamison Firestone