Elliott Brown's killing is emblematic of the difficulty police face in solving homicides in Chicago. It happened about 1:30 p.m. on a busy highway just after the victim had passed through a toll gate loaded with cameras. Brown, a reputed Black P Stones member, had been receiving social media death threats after an ongoing retaliatory dispute with another gang, according to family members interviewed by police. And his girlfriend, Jazmyn Metcalf, who survived four gunshot wounds in the attack, saw the black SUV that pulled alongside Brown's car, but was unable to give police a detailed description of the gunmen. She told the Tribune she was not wearing her glasses when the shooting started.