In 1989, college student Tiffany Sessions seemed to disappear without a trace. A massive search was launched, driven in part by her father, but it turned up nothing. Over three decades later, investigators and her family are still searching for answers. "48 Hours" correspondent Tracy Smith reports. This classic "48 Hours" episode last aired on 8/8/2015. Watch all-new episodes of “48 Hours” on Saturdays and stream on demand on Paramount+.