Article continues below advertisementThe mystery surrounding the disappearance of Nancy Guthrie, the mother of Today show host Savannah Guthrie, has taken a troubling turn after a neighbor recalled spotting a suspicious man in the neighborhood weeks before the 84-year-old vanished.In an exclusive interview that aired Monday night, March 9, on NewsNation, senior national correspondent Brian Entin spoke with a woman who lives around the corner from the missing Arizona resident in the Catalina Foothills area of Tucson.