More evidence in the Nancy Guthrie kidnapping investigation has led to another dead end, according to the Pima County Sheriff’s Office, which is also now facing legal action. Investigators say they were unable to develop a usable DNA profile from a hair found inside Nancy Guthrie’s home. Nanos said investigators have preserved the sample, and it still may be of use later. He added that the sample was just one part of the broader DNA analysis still underway. Pima County Sheriff’s Department via APOther cluesThere is still a mixed sample of DNA retrieved from Nancy Guthrie’s home.