CHICAGO, IL - SEPTEMBER 24: Chicago Police Superintendent Garry McCarthy (C) holds a press conference to announce arrests have been made in last Thursday's mass shooting at Cornell Square Park on September 24, 2013 in Chicago, Illinois. The four men arrested are Kewane Gatewood, 20, Bryon Champ, 21, Brad Jett, 22, and Tabari Young, 22. Police believe the shooting was carried out in retaliation for an unreported shooting earlier in the day when Champ received a graze wound. (Photo by Scott Olson/Getty Images)
