for jarrae, the girl on the conveyor belt. >> it is bad. it was bad. the it was bad. >> strangled, beaten, sexually assaulted, viciously. according to a deputy da larry yellin. >> she should be worrying about grades, boyfriends, and football games. those things. >> one wrong turn and they're gone. >> yeah. >> but almost three weeks in, detective he detective trapp seemed stuck. >> i think she got frustrated and a little desperate and came up with the idea of using the computer database. >> that is the computer database of sex offenders. if they had a serial killer on their hands, there was at least a chance he had already ran a file with them at some point. it was a little bit like putting the finger into that haystack and was trying to