Article continues below advertisementAs Nancy Guthrie remains missing, online sleuths continue to speculate what could've happened to the elderly mother of Today star Savannah Guthrie.One theory that has prevailed since the 84-year-old vanished from her Tucson, Ariz., home sometime in the early hours of February 1 is that members of the Guthrie family could be involved - namely Savannah's older sister, Annie, and brother-in-law Tommaso Cioni.