most of the people corey saw that night left the bar before she did, but one friend, tiffany smith, stayedith corey until 1:00 in the morning. tiffany told police they both left the bar at the same time in their own cars and went their separate ways. but tiffany told friends that wasn't the only contact she had with corey that night. >> she said she called corey from her cell phone around 2:00 a.m. and corey answered the phone. she said when corey answered the phone that corey was asleep and she asked her what she was doing. corey said, i'm sleeping. >> tiffany also told friends she drove to corey's apartment around 4:00 a.m. and knocked on her door, but no one answered so she left. >> her statement that she went by corey's house puts her at the crime scene during the time that corey could have possibly been killed. and that added to that suspicion that she could possibly be involved. >> but when investigators checked tiffany's cell phone records, they made a startling discovery. tiffany didn't call corey after they left the ritz bar. but why would tiffany make up a story like that? >> eve

most famous missing persons cases. 20-year-old college student tiffany sessions disappeared back in 1989. "48 hours" correspondent tracy smithnished. her parents have spent all this time looking for any trace of her, finding nothing. for the past five years "48 hours" has been working this story and now detectives tell us they think they know who killed tiffany sessions. on february 9th 1989 a junior at the university of florida went out for her daily power walk and disappeared. tiffany's parents rushed to gainesville to look fehr her. >> we were all trying to get a handle on what possible explanation. did she have a boyfriend nobody knew about? she didn't have her license. her car was there. that was the scary part. >> reporter: hillary had just seen tiffy at christmas one month earlier. she came up to me and gave me a hug and it was a hug that i'd never had before. it was a very, very long hug and she gave me a big kiss and she said, mom, i love you. >> she would have been wearing some kind of a sweat suit. >> reporter: jim eckert was one of the lead detectives in 1989. >> this woman literally vanished off the face of the