BARNAUL, Russia -- A well-known opposition activist in the Siberian city of Barnaul says he has left Russia after the authorities launched criminal investigations into allegations that he repeatedly violated the law on mass gatherings.

Viktor Rau wrote on social network VKontakte on October 3 that he and his grandson are currently in the Georgian capital, Tbilisi.

"Police have registered criminal cases against me and my grandson Miron due to my opposition activities,” Rau wrote, adding: “The totalitarian authorities do not need dissent, they need to silence people.”

“My motherland, Russia, will be free! I will back someday," Rau said.

Investigations against Rau were launched in April when police searched his home and confiscated his computer, telephone, and 65 posters.

The opposition activist, who has been a vocal critic of local and federal authorities, took part in many unsanctioned rallies in Barnaul in recent years.

Rau tried to get elected to the parliament's lower chamber, the State Duma, last month.

Although election officials initially registered him as a candidate, they later rejected his candidacy, citing his links to groups related to jailed opposition politician Aleksei Navalny that were labeled by the authorities as extremist and banned earlier this year.

Many opposition activists and politicians have left Russia in recent years amid an increasing crackdown on opposition groups and independent media across Russia.