Moscow: Russia’s top prosecutor on Monday accused a major Western investor who fell out with the Kremlin and the US secret services of being behind an opposition film alleging serious corruption among his family members.

An online video released earlier this month by leading Kremlin critic Alexei Navalny’s anti-corruption fund accused the two sons of Russia’s prosecutor general Yury Chaika of illegally amassing large fortunes with the help of officials under their father’s command.

Chaika dismissed the charges in a letter published in Kommersant newspaper and said they were masterminded by American-born Bill Browder, once the biggest foreign investor in Russia, and the US secret services as part of a broader effort to tarnish Moscow’s credibility.

‘I have no doubt that the people that ordered this mendacious film are Browder and the secret services that stand behind him,’ Russia’s top prosecutor wrote.

Browder, who now has British citizenship, has accused Russian tax officials of carrying out large-scale fraud scam uncovered by his late lawyer Sergei Magnitsky but has himself been sentenced by a Moscow court in absentia to nine years in prison.

Magnitsky, a lawyer for Browder’s Hermitage Capital hedge fund, was himself arrested for tax evasion in 2008 and died in a Moscow prison in 2009 after failing to receive appropriate medical care.

In the aftermath of Magnitsky’s death, Browder persuaded US lawmakers to sanction officials allegedly linked to the case by banning them from the United States and freezing their assets, creating deep tensions between Moscow and Washington that resulted in the issuing of tit-for-tat blacklists by the two former Cold War foes.

‘Browder and his bosses in the US secret services have decided to use this [Magnitsky’s] death to the maximum,’ Chaika wrote. ‘It was a lifeline for Browder and the US intelligence services took advantage of the tragedy to launch yet another special operation to discredit Russia in the eyes of the international community.’

The probe into Chaika’s family is the latest into high-ranking officials by Navalny, who has spearheaded protests against Putin’s rule and been repeatedly put on trial in cases he insists are politically motivated.

Chaika said that Navalny had played a ‘very small role’ in the publication of the allegations against his family.