Kristin Smart was near the end of her first year at California Polytechnic State University when she vanished after attending a party in 1996, but it would take years to bring her killer to justice.

In the spring of 1996, Kristin Smart, 19, was a young woman who loved adventure and had her whole life ahead of her. Catch up on Dateline: Unforgettable on the Oxygen App. Then, she vanished. For more ...