According to Censor.NET, the video of the incident was published by LJ user pauluskp. In it you can see that a man who was first knocked down to the ground by a blow into his head and then beat up with rifle butt. Sound of blows, crunching bones, miserable cries for help but none came.
"I'll shoot you, you c#nt!" the "policeman" shouts. "What are you crying for?!" shouts one of the militants, when the unfortunate man started howling in pain.