The Anti-Corruption Foundation (FBK), headed by opposition activist Alexey Navalny, has filed a lawsuit against Russian Attorney General Yuri Chaika, according to a Facebook post by Navalny.

"Today, FBK's legal department filed a lawsuit in Moscow's Presnensky district court against Attorney General Yuri Chaika concerning the professional reputation of the Anti-Corruption Foundation and the protection of honor, dignity and business reputations of the authors of FBK's investigation, including Alexey Navalny," the Facebook message says.

Moscow court officials have not yet issued a formal statement about the lawsuit.

On Thursday, December 4, Chaika told reporters that FBK's investigation is "deliberately deceitful" and has no basis in reality. Chaika also says the report is part of an organized, paid attack on his reputation, and he claims to know who is behind the campaign (though he hasn't yet named anyone).

On December 1, FBK published a large investigation into the illicit actions of Russian Attorney General Yuri Chaika's family. According to the report, the Attorney General's son, Artem, reportedly owns a home in Switzerland and a villa in Greece. FBK says he began his wealth by seizing control over a state enterprise.

Sources in Russia's Federal Tax Service have confirmed to the newspaper Vedomosti that Olga Lopatina, the ex-wife of Deputy Attorney General Gennady Lopatin, did in fact co-own a company with the wife of Kushchevskaya mob boss Sergei Tsapok. Hours before this report, Lopatina claimed through the Attorney General's office that she co-owns nothing with anyone connected Tsapok's gang.