cop grabbing demonstrator while being detained on sidewalk for "jaywalking"

this is when the 4 cops drove their motorcycles at us on the sidewalk and cut off our path. (just before another 19 cops showed up and sorounded us).. Look at the area I lightened up in this shot. You can see (in the windows reflection) the cop grabbing this demonstrator on the arm. The PEACEFUL demonstrator was telling the cop to get his hands off him at this point.

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