Dallas police are searching for a driver they say fatally struck three men and injured two other people early Sunday before abandoning his 13-year-old passenger at the scene.
The victims had stopped their Toyota Rav4 to change a flat tire along Interstate 635, just west of the Dallas North Tollway.
The Dallas County medical examiner's office confirmed the three killed were Hieu Minh Doan, 22, Christopher Phan, 23, and David Nguyen, 23.
The 22-year-old's mother, Minh Dang, told KTVT-TV (Channel 11) that her son graduated last year from the University of Texas at Dallas with a degree in biomedical engineering. He was driving with his four friends after a concert when they got a flat tire.
About 3:30 a.m., a pickup hit and killed the three men who'd been working on the tire, then hit the Toyota, injuring a man and woman inside.
The woman, who was severely injured, and the man, whose condition was not released, were hospitalized.
The truck driver, who has not been identified, fled the crash on foot, leaving a 13-year-old boy behind.
The teenager was reunited with his mother at the hospital, police said.
The driver faces charges of manslaughter and failure to stop and render aid.