I watched hundreds flood the South End after 2 a.m.; what began as street racing became violent when participants blocked intersections, hurled cones and fireworks, and set a Boston Police cruiser ablaze. Two Rhode Island men were arrested and later released on modest bail as investigators review video to identify more suspects. The scene - captured on multiple videos - shows the danger to bystanders and officers, and city leaders are calling for tougher enforcement and faster identification. If you have footage, upload it to authorities with time and location. We will update this post.