A bright future was shattered when newly engaged Kevin Jiang, 26, a Yale graduate student and former Army National Guardsman, was gunned down in New Haven, Conn. What appeared to be a road rage incident soon unraveled into a story of obsession and premeditation.

For years, the death of 15-year-old Danni Houchins had been shrouded in mystery. Investigators initially said it could have been a tragic accident, but her family always suspected something more sinister. 48 HOURS and correspondent Peter Van Sant report on the case in "It's About Danni,"