joe kovac: theres another level of evil here. the person who did this was trying to create a vanishing. craig melvin: who could do such a thing? steve gatlin: first thing you look at whos closest to her romantically or geographically. craig melvin: the list was long. a boyfriend, an ex and fellow students. had somebody been studying more than textbooks? david cooke: he would ask other people, how would you commit the perfect murder? mike burns: his roommates said he always thought he was smarter than everybody else. smarter than law enforcement. craig melvin: smart, maybe. but had he slipped up? david cooke: what they found told us everything we needed to know. craig melvin: a confounding case that would come down to a damning piece of video that no one was supposed to see. ashley muller: sick, twisted. keith morrison: what was it like to see that? david cooke: i knew we had him. craig melvin: hello and welcome to dateline. lauren giddings moved south for law school and immediately felt right at home. smart and vibrant, she turne