[Warning: Potentially Triggering Content] Authorities say the man who opened fire Thursday morning on the campus of Old Dominion University in Norfolk, Virginia - leaving one person dead and others wounded - had a disturbing history that investigators are now examining closely. And the details emerging are as troubling as they are heartbreaking. According to senior law enforcement officials who spoke to NBC News on Thursday evening, the gunman who killed one at ODU has been identified as 36-year-old Mohamed Bailor Jalloh of Sterling, Virginia.