reporter: it was one weird triangle. the prosecution argued that daniel felt left out, became increasingly jealous and then angry. and then his anger turned to rage at shelley. that s why this whole thing happened. i believe he had hate in his heart for her. reporter: but remember, in a court of law, a defendant is innocent until proven guilty. and daniel? my mother asked me if i killed shelley. and i told her, mama, i m not the one who committed this. i m not the one who killed her reporter: coming up, daniel s defense tries a single, bold tactic to cast suspicion on nathan. and they ve got plenty of ammunition. what they had in their pocket is the boyfriend, who we knew the girlfriend was thinking about breaking up with, who happens to be obsessed with knives. reporter: what would the jury make of all that? imagine if we ever got to meet.
mode. and it s like, okay, if it was her, is it gonna be me next? in fact, in short order, the art institute of dallas moved its students out of the falls and into a more secure apartment complex in a safer part of town. but with the investiga just days old, they didn t know what police were thinking. that this was no random crime that it was personal, an inside job, so to speak. they were looking at people close to shelley. someone who had a key. like a boyfriend or a roommate. someone who knew she d be asleep, and then surprised her, attacked her with a knife. she was small in stature. she was a little girl. it wouldn t take much. but who? as tough as detective ellzey was with roommate ashley and boyfriend nathan, he was not much farther along than when he started. and so he spent some time with a few of nathan s friends, like his roommate, daniel willyam.
he was at school when we believe shelley was killed. reporter: but daniel? daniel, remember, had given the police a shifting alibi. didn t tell them in his first interview that he stopped by a walmart store to buy hair dye. but, as detectives thought about it, that new little nugget raised more questions. i mean this is a young kid not old enough to have to cover, you know, whatever they re covering. i mean he his hair looked fine to me. i thought it a little odd. reporter: did he actually go to walmart at all that morning? they subpoenaed this walmart surveillance video and sure enough, there was daniel. in the walmart when he said he was. but why hair dye? could it be he really wanted the protective gloves that are generally included in a hair dye kit? gloves is important because there s evidence at the scene where a glove turned up. reporter: not a whole glove,
he was asking her in those text messages if she wanted to go to lunch with him. he was hammer texting her. and it was one of those situations where i have no doubt in my mind, he was texting her to see whether or not she was gonna leave that classroom. she repeatedly told him no, that she was in class, that she wasn t interested. and the fact that he kept asking just showed that he really wanted to make sure he could get away with what he was about to do. and that she wasn t home, also. reporter: right. so that was key. he had to make sure that there was nobody in the apartment. absolutely. reporter: then daniel stopped texting her for almost two hours and then resumed again. and remember, in his first interview with the police, daniel lied about where he was the morning of the murder. and then in a second interview, he told them he went to the falls that morning. and that bit was true, the prosecutor said. but when daniel claimed he went there to meet another female classmate
to have ever been there. he didn t contact her about coming in and doing any such project. and so then the other lie, though, was in that he then told the detectives about going straight home. and when the detectives started to look at the cell phone records of his location after we believe he committed the offense, he went to an entirely different location. reporter: didn t go home? he did not go home. he went 30 minutes north of town, stayed up there for some period of time before coming back. reporter: getting rid of his bloody clothing and the murder weapon and other evidence, the prosecutor figured, none of which police were able to find, though they searched thoroughly through the area. in this case, we had someone who committed this crime and then did a fantastic job of cleaning up and not leaving evidence and after the fact told multiple lies. reporter: in fact, the prosecutor said, daniel was so good at cleaning up it would be reasonable to assume he was framing nath