A group of young people participates in a protest that turns violent. A police officer sees a man wearing a blue hooded sweatshirt throw a brick, which ends up injuring a passer-by. The officer follows the man, but the man ducks behind a building, out of sight. A few seconds later, a man wearing a blue hooded sweatshirt emerges from the building. The officer identifies him as the same man who threw the brick and promptly arrests him. The man is put on trial in what prosecutors see as a cut-and-dried case. But the man protests his innocence, saying that he was merely leaving the building and that he didn’t even know about the protest, let alone participate in it.