I was there too. Im glad this issue is brought up, I was starting to think that it was going to go unnoticed. What Pepper said is true.. Here's my take:
I was watching the concert and all of a sudden I see a scuffle right next to me. I look over and see some pushing and shoving. (I do not know the reason). At this point, the cops step in and a large, tall, bald cop hits Hicks in the face. Hicks then goes to the ground. The cop hits Hicks again and knocks Hicks unconscious. This was probably necessary just to be able to arrest Hicks. At this point, the cop should have flipped Hicks over and arrested him because he was unconscious. That did not happen. After the second punch, which knocked Hicks unconscious, the large bald cop continued to punch Hicks in the face for 25 seconds minimum. I could feel the ground shake from Hicks' head bouncing off the ground. I literally thought that Hicks was dead after the cop stopped beating his face in. I am a fan of cops 99% of the time, but not in this case. This was, without question, police brutality and justice needs to be served.