>> even those who live in st. louis county are unsure about what might happen. it is like your city is about tote get hit by a hurricane but you don't know if it is a category 1 or a category 5. police acknowledge they expect disruptions. they just don't know how severe. listen to what some of the protesters were saying last night before the violence broke out. [ chanting ] >> ready for war. then hours after mostly peaceful demonstrations, the tension level increased. rival groups showed up with guns. when the shots rang out, cameras were rolling. watch again. >> behind the engine block. >> behind those shooting, was