A new tip has sparked a search in Mexico for missing 84-year-old Nancy Guthrie, the mother of Today show host Savannah Guthrie. A volunteer search group in Nogales received an anonymous claim that Nancy had been buried in a stream bed near the Arizona-Mexico border. Searchers quickly investigated the location, but found no sign of her remains. Despite the dead end, the volunteer group says it will continue searching. Authorities in Arizona confirmed they are aware of the reports, but say Mexican officials have not contacted them. Investigators stress that the case remains active and they are still pursuing credible leads.