MOSCOW (AP) — A Moscow court has sentenced a man who claimed to be a bystander at a summer opposition protest to 3 ½ years in prison.

The court on Monday found Pavel Ustinov guilty of assaulting police during a July 27 protest in Moscow.

Ustinov became the fourth person this month to be convicted and sentenced to prison for assaulting police.

Prosecutors said that a riot policeman dislocated his shoulder while detaining Ustinov. Footage from the scene showed several officers tackling Ustinov as looked at his phone while standing on the sidelines of the protest.

Protests erupted this summer after Russian election officials disqualified a dozen independent Moscow city council candidates. Government critics say protesters are being put on trial to intimidate opposition supporters.