The decision by investigators to withhold purported ransom notes in the ongoing search for Nancy Guthrie is puzzling, one former FBI agent told Newsweek . Andrew Bringuel, a retired FBI agent who runs a private security consulting firm in New York, said a cooperating witness likely represents the "greatest chance" for detectives to identify and arrest those responsible for the disappearance of the 84-year-old Arizona woman who is the mother of Today co-host Savannah Guthrie. "Because in this