MOSCOW, October 23 - RAPSI. Left Front movement coordinator Sergei Udaltsov and his attorney Violetta Volkova have been called to the Investigative Committee on October 26 to be charged with preparing mass riots, Investigative Committee official spokesperson Vladimir Markin told journalists on Tuesday.

The authors of the film, "Anatomy of Protest-2," have claimed that the opposition is preparing a coup d'etat financed from abroad. A case on charges of preparing mass riots has been initiated.

Udaltsov could face from four to 10 years in prison. Earlier, prosecutors brought charges against Udaltsov's aide Konstantin Lebedev and opposition figure Leonid Razvozzhayev.

The Investigative Committee took a close look into the Udaltsov after the "Anatomy of Protest-2" documentary was broadcast by NTV.

The filmmakers claim that the opposition has been preparing a coup using funds and militants from abroad. The film shows Udaltsov and his companions talking with the then Georgian parliament's defense and security committee head Givi Targamadze, who is said to be experienced in planning "color" revolutions in Georgia and Ukraine, as well as mass riots in Belarus.

The investigation into the film has established that the voice in the scenes filmed by a hidden camera was Udaltsov's and that the meeting shown in the film took place in Minsk in late June 2012.