>> of course, we wanted to know why. was he the killer or was he not? >> the detective was determined to answer that question. so, he put the young man under surveillance, followed him to a local restaurant. >> and are you hidden somewhere in the restaurant? >> i'm kind of back in a corner, yeah. >> he watched the student have a few drinks, and when he left, the detective snagged the dirty beer mugs and sent them out for dna testing. the results would take weeks, leaving a town full of young people on edge. >> dads and moms were telling their college age kids, be alert everywhere you go. go with people when you go out. don't be alone. and that's a frightening order to give anybody. >> frightening, but sound advice, because in this case, connecting the dots wouldn't be so easy. coming up, detectives have a second possible suspect in their sights. jamie's boyfriend is invited to sit down for a polygraph test. >> failed the test.