The Russian Prosector General's Investigative Department also told the defendant's family that if they do not consent to closing the case, all results of the investigation will be publicized in court.
The officials were reacting to Magnitsky's relatives and colleagues, who insist on a full investigation into his death.
Hermitage Capital Management says Magnitsky was arrested and subsequently died after uncovering a US$230 million tax fraud. Two tax officials that Magnitsky linked to the theft left Russia last May, according to a recent report the Federal Security Service (FSB).
Investigators maintain that it was Magnitsky and his accomplices who stole the money, and a Moscow court recently ruled that prosecuting him posthumously was not against the law.
Yesterday, the British House of Commons unanimously passed a bill in favor of imposing visa sanctions and asset freezes on the Russian officials they believe were involved in Magnitsky's death. This follows a similar move last year by the U.S. Government.