Event: Catalina Foothills

There's a different kind of depth to the darkness at nighttime in the upscale Catalina Foothills neighbourhood of Tucson, Arizona.Lights are limited by both the county and the homeowners' association; they must be shielded and can only face down, a deliberate effort to maintain Tuscon's "dark sky" status - designed to minimise light pollution, reduce energy waste and protect astronomical research at nearby facilities.The result is a quiet, peaceful blackness making Catalina Foothills the perfect spot for stargazing - or for furtive criminal activities like kidnapping an elderly woman.That's what happened overnight on 31 January, when 84-year-old Nancy Guthrie, mother of US television presenter Savannah, was pulled from her bed. The assailant - or assailants - vanished into the "dark sky" night with the church-going grandmother.And the case ever since has been nearly as obscured as the Catalina Foothills after nightfall - beset by everything from tricky terrain to law enforcement infighting. The list of challenges facing the investigation into Nancy Guthrie's disappearance goes on and on - and perhaps goes some way toward explaining why answers remain elusive nearly five months after the 84-year-old was abducted from her Arizona home.The lack of resolution, with no suspects identified and no information as to where Guthrie was taken, is all the more perplexing given the spotlight that's been on the case from the outset thanks to the celebrity of Guthrie's daughter, famous US news presenter Savannah.Law enforcement consultants, media and citizen sleuths have been poring over the case with no success - and details made public this week from ransom notes raise only more questions.The Guthrie family believes the notes, received in the days after the crime, to be real. One of them allegedly demanded millions in bitcoin, the second allegedly said she had died, while expressing regret on the part…