There were several threads on this story this morning...the guy you are talking about had his van attacked by the mob/protesters and may have knocked one or two to the ground as he drove very slowly (<5 MPH) over to the cops who ignored his predicament.
Those same cops suffered injuries a little later when the mob unleashed their anger on them...tossing full soda cans at the cops and the folks who attended the rally for MMP co-organizer Jim Gilchrist.
Thanks for the clarification
The Brown Berets were hurling frozen soda cans the last time they attacked a group of elderly Americans at one of these events. This time I've heard the soda cans were filled with marbles.