Born in 1977. Under house arrest (as of October 2013).
On 26 October 2012 Udaltsov was accused of preparing mass riots. The accusation was based on a recorded conversation. The recording was used in the «Anatomy of Protest-2» documentary. The Investigative Committee ruled to impose travel restrictions on Udaltsov.
The Moscow’s Basmannyi Court chaired by judge Karpov on 9 February 2013 satisfied the request of investigator Gabdullin and put Sergey Udaltsov under house arrest.
The Investigations Committee announced, on 10 January 2013, that the Bolotnaya Square case and the so-called “Anatomy of Protest” case will be united, as, according to the investigators, these crimes have been committed by the same group of people.