The Kuibyshevsky District Court in Omsk fined Tatyana Schneider, head of the regional branch of Russia's Yabloko party, 10,000 rubles on October 21 in an administrative case involving alleged incitement of hatred or hostility.
The case centered on a comment allegedly posted on VKontakte in 2011. Schneider denies writing it.
The proceedings were brought under Article 20.3.1 of Russia's Administrative Offenses Code, which provides penalties for inciting hatred or hostility and degrading human dignity.
According to Yabloko, representatives of the social network were unable to verify who had authored the comment because the information, dating back 15 years, was no longer stored on the company's servers.
Schneider also said her accounts had been hacked repeatedly. Despite those circumstances, the court found her guilty.
The proceedings had become public earlier, after Schneider was summoned to the prosecutor's office. The latest ruling represents a new development in the case.
Yabloko links the prosecution to Schneider's political activity. She had been among the leaders of the party's federal candidate list in the State Duma elections. This is the party's assessment, not a motive established by the court.
The case raises questions about the reliability of evidence and the attribution of social media posts made many years earlier.