i'm shannon melendi. welcome to our special segment on-- anne martinez vasquez: when i look at that video, it's definitely a sweet memory. i look back at how just innocent we were. luis melendi: shannon was someone that wanted to live. dennis murphy: but then came that phone call, way back in march 1994. shannon melendi's little sister, monique, was just 13 years old. and i received a phone call from her roommate. dennis murphy: shannon was midway through her sophomore year at emory university in atlanta. monique answered the call at their childhood home in miami, and on the other end of the line was athena, her sister's college roommate. athena was very distraught and was asking me frantically if i had heard or spoken from shannon. dennis murphy: shannon hadn't been seen or heard from in more than a day. now, are you starting to do the calculation, even at the age of 13, that this is trouble? i was. i knew immediately that something was terribly wrong. dennis murphy: monique hung up with the roommate and

dennis murphy: and monique has a keepsake that ensures shannon is with her every day on her finger. monique melendi: this was the infamous ring that he had taken from her. saying this is the evidence that i have her. i'm guessing that ring and you are never separated for very long. no. no. it makes me feel very close to her. that's all for this edition of "dateline." i'm craig melvin. thank you for watching. [music playing] i'm andrea canning, and this ithat she met him in a bar..cd she was smitten. she really went all out for him. she couldn't see the red flags. andrea canning: it was a heartbreaking case. jill mccluskey: i just didn't realize how much in danger she was. diamond: one of our friends actually looked him up and was like, this is not the guy that you think he is. he conned women to get what he wanted. and he was good at it. he was very good at it. matt mccluskey: he had been peeking in her dorm room window. jill mccluskey: lauren kept saying, well, the police will handle it. diamond: we got the notification on our phone saying, lockdown at the u. jill mccluskey: he had been lying in w