The disappearance in Arizona of the Today show host Savannah Guthrie’s mother has captivated the nation

Nancy Guthrie disappeared from her Tucson, Arizona, home two weeks ago, setting off a potent chain reaction of federal and local criminal investigation, amateur sleuthing and public obsession that – so far – has resulted in neither the 84-year-old grandmother being located or anyone named as a suspect or, indeed, arrested.

It is a case that is both enthralling and baffling the American public, casting doubts on the ability of investigators to get to the bottom of the mystery that each day generates a fresh 24-hour news cycle – but seemingly little in the way of solid fresh leads likely to solve the case.