A hair sample found at the home of Nancy Guthrie came back inconclusive after undergoing testing, Pima County Sheriff Chris Nanos revealed Thursday.

Pima County Sheriff Chris Nanos said authorities are “working this as hard as we can” after Savannah Guthrie’s latest plea for the return of her missing mother.

Pima County Sheriff Chris Nanos shares new update on the 84-year-old Nancy Guthrie's case after Savannah released the new plea.