When police arrived after reports of a shooting over the weekend at a bar outside Chicago, witnesses say Jemel Roberson, a 26-year-old security guard who worked there, had already subdued the alleged assailant in the parking lot, pinning him to the ground. Adam Harris, who was at Manny's Blue Bar in Robbins at the time of the incident on Sunday, told WGN-TV that Roberson was holding "somebody on the ground with his knee in his back, with his gun in his back" when officers from neighboring Midlothian got there early Sunday. Midlothian Police Chief Daniel Delaney said that's when one of his...