Article continues below advertisementDNA evidence collected from Nancy Guthrie's home continues to undergo testing at the FBI's crime lab as the investigation into her disappearance hits the 100-day mark. Today star Savannah Guthrie's 84-year-old mom vanished from her Tucson, Ariz., area home in the middle of the night on February 1. The DNA sample was originally sent to a private lab in Florida by local authorities before it was transferred to the FBI's high-tech laboratory in Quantico, Va., weeks later.