In an interview with our Liz Kitz, Puma County Sheriff Chris Nanos says he might be deploying genetic genealogy, which compares DNA extracted from a crime scene to DNA databases, using familial matches to narrow down the search. In the case of the unknown DNA found inside Nancy Guthri's home, the sheriff says the DNA samples are mixed. And because of that, genealogologists say the process could be more complicated.Genealogy is really good with low-level DNA, degraded DNA, but it's not good with mixtures. Th ...