Savannah Guthrie has issued a public plea for information about her missing mother, Nancy Guthrie, as the search enters its third week in Tucson, Arizona. A fourth potential ransom note has surfaced claiming Nancy was taken across the border to Mexico, approximately 75-80 miles south of Tucson. The FBI is conducting DNA analysis on gloves found at the scene and checking results against multiple databases, though law enforcement has expressed scepticism about the authenticity of the ransom notes received so far.