Gunman opens fire from rooftop in Chicago suburb | Nightline
At least six people were killed and 24 were injured in the shooting, officials said. WATCH NIGHTLINE EPISODES: https://abc.go.com/shows/nightline ALSO AVAILABLE ON HULU: https://hulu.tv/2wSmSrZ #nightline #chicago #massshootings #gunviolence #crime #abcnews…