>> it was my first girlfriend. >> reporter: detective ellzey had never heard of a college romantic relationship like that. question was, could he believe it? >> how many 19 and 20 year old people proclaim to have a girlfriend or boyfriend who have not kissed them? >> reporter: nathan also said he hadn't seen or spoken with shelley since several days before the murder. in fact, he said, he spent much of the week back home with his mom and grandmother. was he telling the truth? standard procedure -- detective ellzey checked out nathan's body for scratches. >> all right, turn around -- okay turn back around again. how did you get those scrapes? right here, them scratches? >> oh, i actually, i scratch myself. >> reporter: again, could he believe that? >> we asked him, "can we go to your apartment?" you know? "describe your apartment. do you have knives? do you have swords? do you have this?"