to collect dna, the composition of the body, whether it was outdoors apparently, how does all of that factor in? >> number one, the dna is going to stay despite any decomposition. normally, if the body has deteriorated a great deal, the soft tissues, skin and muscle, the dna can be extracted from the leg bones. that's not a problem. that stays good for decades, in the bone and teeth. she had other ways of being identified also. dental records that she had from dental identification. from x-rays that she might have had and also, she had very characteristic tattoos that show up on the video when the police interviewed her and her boyfriend. >> shannon: doctor, what about the dna from someone else, whether it's the boyfriend or someone else, also being present