nikki whitehead was a single mom working towards a brighter future. at dream died when nikki was viciously murdered. her death left her teenage girls seemingly inconsolable, and investigators were committed to solving her murder. the answer would prove elusive. in the end, difficult for even the veteran detectives to believe. here is keith morrison with bad blood. >> once in a while, in a complicated life, a woman can get lucky. which is why you are looking at the sweet little town called conyers, georgia. and deep downtown, with gated communities, good schools, it was pure luck that brought nikki whitehead to this house, in this quiet, safe neighborhood. just far enough away from atlanta, that capital of overheated ambition down the drive. here in conyers, she could give her beautiful twin daughters a better life than hers. but of course, luck, fortune and fate can go either way. sometimes, in ways very hard to comprehend. >> everything about this goes against nature. >> how can somebody do that? >> it was definitely the bloodiest crime scene i had ev