>> there could be somebody up there right now. >> yeah. >> and just depending on where they're at, you wouldn't even see them up there. >> reporter: detective todd babcock and sergeant lou heckroft drew the job of trying to track downtown killer. all they knew was that he'd killed at least 11 women and that the 2005 housing boom that brought suburban sprawl to the west mesa probably forced him to abandon this burial ground and find another one where there would be no neighbors around to watch him work. >> you're up half a mile to 3/4 of a mile from any populated area back in the time frame. >> reporter: a time frame, 2003 to early 2005, and 11 sets of bones. not a lot to go on. but the detectives knew simply finding the bones in the first place had been an incredibly lucky break. >> all the stars aligned. yeah. >> reporter: oddly enough, the