piled onto the grief of the nance family in 2009. >> it's kind of scary that somebody could be out there that's capable of doing these type of things. >> reporter: the answer wouldn't bring her back, of course. nothing was going to be the way it was ever again. but finding out who did it? now that was a need. intense. the dallas police department was zeroing in on the boyfriend, nathan. and so detectives decided to interview daniel a second time. after all, he lived with nathan. maybe daniel could tell them more. and then something odd happened. daniel changed his own story a little. remember the story of where he was day of the murder? this time, he added something. 10:15 to 10:20 you were at starbucks. where did you go? >> to white rock lake. >> okay, specifically at white rock lake, where?