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? and he answered kind some some weird stuff. reporter: funny thing is, he did. he did. and what a collection he had. he had throwing stars. he had daggers. he had knives. he had swords. who collects that kind of stuff? reporter: then detective ellzey learned something very interesting from shelley s mom something shelley had told her mom not long before she was killed. she said, mom, i m thinking about breaking up with nathan. she said, i just don t have the feelings for him that i think i should. you know, i just don t, you know, don t see the relationship going anywhere. reporter: had a furious young man struck back at the woman who rejected him? a not uncommon motive for murder, as the detective knew very well. he confronted nathan.
shelley told her mom that she told you that ya ll were through. no. ah, yeah. no, she didn t. her mama told me that. son, i talked to her mama. don t call me a damn liar! i just talked to her mom her mama, shelley told her mama that ya ll had had nothing in common. and that it was over. that it was through. she never said that. boy, you sound like mad. you re a damn psychopath. are you like coo-coo-coo and la la land? does [ expletive ] not register to you? nothing makes sense. i m just i m just waiting to wake up. that s right. you re waiting to wake up. now, what did you do with the knife? i wasn t there. nathan, you i didn t do anything with a knife. yeah, you did. reporter: detective ellzey made no apology for the aggressive tone of his interrogation. there was more to learn about
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.
and the police showed up. and they grabbed him by the arm and yanked him out the door and they started talking to him. not gently? no, no. they were talking to him and then they got in the car and went. and i didn t see him for the rest of the day. reporter: in a murder so up close and personal so vicious boyfriend nathan naturally became a person of interest immediately. when officers brought him to dallas police headquarters, detective ellzey was more than ready to ask nathan some very personal and specific questions about his relationship with shelley. are you a virgin? yeah. is shelley a virgin to your knowledge? y all ever discuss sexual intercourse? never? she s been in your bedroom before with the light off. yeah. what do you all do? we were sitting there playing video games. you never tried anything sexual with her?
sure it did not come from the medical examiner or any of the officers at the crime scene. and it did not. must have been left by the otherwise careful killer. but who would want to hurt her? and so horribly? the first person detective ellzey talked to was shelley s roommate, ashley olvera, who d found shelley dead in her own bed. that s how ashley became possible suspect number one. she wasn t sexually assaulted, shelley. that was my initial opinion. it was later confirmed. reporter: yeah. why couldn t a woman do this? reporter: sure. it s her roommate. there s a lot of things happen between roommates that we don t know about. so it very well could have been. reporter: sure. what happened, if anything, between these roommates was something detective ellzey was determined to find out. even if he had to get rough. coming up right away, he would become convinced that something just