"i wanna know what happened to my mom." and he just said -- "you know, you need to keep pushing" and that's all he'd say. >> reporter: so she did. brittany says she began calling the prosecutor's investigator every week like clockwork. and amazingly he started showing some interest in the case. >> and he'd say, you know, "nothin' new," or -- >> you're looking for a killer? >> right. >> is he looking for a killer or just trying to find out what happened? >> i think at that point at first he was just trying to put the pieces together. >> reporter: it wasn't going to be easy. what brittany didn't know was that detective bratton had done a fair bit back in the day, chasing down leads, trying to make sense of it all, but interview tapes, crime scene photos, evidence --most of that was missing. >> not to beat people up, but what happened to all those boxes, the interviews, the pictures, the measurements --it seems like it disappeared, just vanished. >> to the average person that's probably unnexcusable and why did it happen?