The Presidium of Russia's Supreme Court has set aside the conviction of political activist Ildar Dadin on charges of participating in multiple unsanctioned protests and has ordered his release from custody.
The presidium on February 22 ordered the case against Dadin closed.
Dadin, who has been listed by Russian and international organizations as a political prisoner, was serving a 2 1/2-year prison sentence after being convicted under a controversial law that criminalizes participation in more than one unsanctioned protest in a 180-day period.
He participated in the presidium's hearing by video-link from prison.
Deputy Prosecutor-General Leonid Korzhinek told the hearing that Dadin's conviction should be voided because there was a lack of evidence that a crime had been committed.
Dadin's wife, Anastasia Zotova, told Dozhd TV that her husband would be released when the court's order was conveyed in writing to the prison where he is being held.
"If it is done by electronic mail, he could be released within the hour," she said. "If they send it by ordinary mail, it usually takes two weeks."
On February 10, the Constitutional Court upheld the law itself but ordered a review of Dadin's case, saying the application of the law should be determined by "the real scale of public danger" presented by the defendant's actions.
Dadin was convicted in December 2015 and served more than one year of his sentence. His lawyers said on February 22 that they have not yet decided whether they will seek compensation from the government.
Dadin, the only person in Russia who has been convicted under the law, last year wrote an open letter alleging that he and other prisoners had been beaten and tortured at a prison in the Karelia region. He was later transferred to a prison in the Altai region.
The decision of the Presidium of the Supreme Court is final.
Opposition politician Aleksei Navalny, who has announced his candidacy for the 2018 presidential election, said on Twitter that "it is important to remember that [Dadin], an innocent man, was held for a year and a half in prison and tortured."
Zotova told Dozhd TV that she welcomed the court's decision but was worried her husband might be rearrested shortly after his release.
Zotova credited international attention concerning the case as playing a crucial role in the Russian courts' decisions, saying that a similar thing happened when the Russian government agreed to release Ukrainian military aviator Nadia Savchenko last May.