her and mollie as "girl one" and "girl two." >> he used numbers in that other crime? >> yes. >> they referred to each other by number in that particular crime. >> reporter: the similarities between the two crimes didn't end there. >> in the nevada home invasion, were the victims bound? >> yes, they were. >> he's gotta be number one on the list at this point. >> he -- he definitely jumped to the -- to the top. >> reporter: by that time, dylan spellman had already returned to nevada to begin serving his three-year sentence. so chavez hopped a plane to las vegas, hoping to hear what mr. spellman might reveal about his brief stay in texas. spellman admitted he was in the park the night of the shootings. but he denied being anywhere near the area where the girls were found. >> he said he was never on the deck. well, we've got dna on the cigarette butts that prove otherwise. >> why lie about that unless you're involved in the crime? >> sure. so, i mean, it -- that definitely raised more suspicion. >> reporter: chavez then told