Police superintendent draws a distinction between protesters and criminals . The police chief says the protests are not about any particular issue but rather to express their anger over what they see as unfair treatment by police. Protesters rally outside the Chicago campaign headquarters of Obama . Dozens were injured in clashes between police and protesters Sunday .
Police superintendent draws a distinction between protesters and criminals . Obama says police did a `` great job under some significant pressure '' Protesters rally outside the Chicago campaign headquarters of Obama . Dozens were injured in clashes between police and protesters Sunday .