A district court in Moscow authorized on Thursday the arrest of an aide to prominent opposition figure Sergei Udaltsov on accusations of planning an anti-Kremlin coup.

The Investigative Committee pressed charges against both Udaltsov and his allies Konstantin Lebedev and Leonid Razvozzhayev.

But Udaltsov was allowed to stay at large after questioning on Wednesday, while Lebedev was placed in detention until mid-December after investigators claimed in court he is liable to flee the country.

Razvozzhayev, who works for A Just Russia’s Ilya Ponomaryov, faced no sanctions so far because the investigators failed to locate him.

The three face up to 10 years in prison on charges of conspiring to organize mass disorder.

The charges are based on Anatomy of a Protest 2, a sequel to a documentary on the Russian opposition aired by NTV, a privately-owned but fiercely pro-Kremlin television channel.

The film, aired on Oct. 5, claims that Udaltsov and his supporters planned to stage mass riots and a coup using funding from the Georgian leadership, which is at odds with the government of Russian President Vladimir Putin.

The documentary comes complete with footage of Udaltsov’s alleged meeting with a Georgian representative to discuss plans for the rebellion. NTV said on Thursday the video was handed to the channel’s correspondent in the street by a Georgian national who walked away without identifying himself.

Udaltsov, one of the leaders of the unyielding anti-Kremlin protests that have continued in Moscow since last December, slammed the documentary as “delirious nonsense.” He and other opposition figures claimed earlier that the Kremlin has initiated an intimidation campaign against its opponents in recent months, passing restrictive political legislation and conducting searches in protest leaders’ homes.

In July, the Investigative Committee charged whistleblowing lawyer Alexei Navalny, another major opposition leader, with large-scale fraud, punishable with up to 10 years in prison. Navalny has dismissed the case as politically motivated.