Officer Wounded, 3 Dead In Interstate Shootout POSTED: 8:17 am CDT August 12, 2007 UPDATED: 8:49 am CDT August 12, 2007 DALLAS -- Three people were killed and a Dallas police officer wounded in a bizarre shootout on Interstate 35 early Sunday morning. Police were called to a "major accident" on the interstate about 2:15 a.m. When they arrived, they found two people suffering bullet wounds, laying on the freeway several yards apart, police said. As two officers were trying to help the victims, someone fired on them, striking Cpl. Jerry Poston, a 17-year veteran of the force, police said. As Poston's partner frantically called for help, several passersby stopped to assist. They, too, were fired on. One of those passersby returned to his car, grabbed a handgun and shot down the suspected gunman, police said. Poston was listed in serious but stable condition at Methodist Central Hospital in Dallas, police said. Detectives remained on the scene late Sunday morning, still trying to sort out exactly what happened and identify the people killed. All were men, they said. Police also said they recovered a shotgun at the scene. Southbound I-35 remained shut down between Oak Lawn Avenue and Colorado Boulevard at 8:15 a.m. Sunday. Stay with NBC5i News and NBC5i.com for the latest details.