paige whitney, alex's swim team pal knew that. gone through high school with clayton, sat beside him in senior year math class. >> she felt like he deserved a lot more and that she was very, very lucky. >> really? >> yeah. >> so she considered herself lucky that he had chosen her? >> absolutely. >> watching them together, did it seem that he really cared about her, that he really liked her? he was -- >> absolutely. >> happy to be in that relationship? >> yeah, you know, you see them laughing together. you see them, you know, getting along so well. >> reporter: their twitter messages were light-hearted. they called each other "dork" and "freak" and lived out their lives in the twittersphere. before clayton arrived that friday, alex had tweeted "ahhh see you soon." her family liked him, too. they'd given him a care package for her; and her mom had contributed $20 towards gas for the trip. >> reporter: once alex's swim team meeting ended that day, the couple met up, had some alone time in her dorm room, then went to dinner. alex and

paige whitney, alex's swim team pal knew that. she'd gone through high school with clayton, sat beside him in senior year math class. >> she felt like he deserved a lot more and that she was very, very lucky. >> really? >> yeah. >> so she considered herself lucky that he had chosen her? >> absolutely. >> watching them together, did it seem that he really cared about her, that he really liked her? he was -- >> absolutely. >> happy to be in that relationship? >> yeah, you know, you see them laughing together. you see them, you know, getting along so well. >> reporter: their twitter messages were light-hearted. they called each other "dork" and "freak" and lived out their lives in the twittersphere. before clayton arrived that friday, alex had tweeted "ahhh see you soon." her family liked him, too. they'd given him a care package for her; and her mom had contributed $20 towards gas for the trip. >> reporter: once alex's swim team meeting ended that day, the couple met up, had some alone time in her dorm room, then went to dinner. ale

sandra whitney is a good friend of alex's parents. she is paige's mom. >> they had gone off for a weekend vacation. they had been texting that evening and becky was sending her pictures of the hotel room. and alex didn't respond. and she tried over and over again and she didn't respond. that is not how their relationship worked. you text, you call. you always responded. >> is that unusual that she wouldn't respond in college. it's the weekend, her boyfriend is coming for the weekend. >> i imagine the first couple of times maybe she wasn't concerned. when it was several that's what raised flags. >> was it a little bit of mother's intuition? >> i imagine it was. >> alex's mom worked the phone frantically trying anyone who might know where her daughter was. at 2:24 a.m. she called the campus police to ask them to go to her daughter's dorm room to check on her. >> you took that call? >> i did. >> you headed to the dorm. >> yes. >> and then what happened? >> we went there and knocked on the door. i knocked twice and since it was a welfare check i said le