A retired FBI special agent revealed what she thinks is a "critical" factor that could prove pivotal in solving the Nancy Guthrie case, as she remains missing.

Nancy Guthrie has been missing for over five months after her abduction in Tucson. The FBI is investigating ransom notes, with mixed legitimacy.

A retired FBI special agent revealed what she thinks is a "critical" factor that could prove pivotal in solving the Nancy Guthrie case, as she remains missing.