The longer it drags on, the more uncomfortable the questions become. As the desperate search for Nancy Guthrie enters another agonizing stretch, scrutiny is no longer focused solely on the person or people who took her, but on the very law enforcement agency tasked with bringing her home. And behind the scenes of this now-national nightmare, sources are painting a troubling picture of an investigation helmed by embattled Pima County Sheriff Chris Nanos that may be far more fragile than the public realizes.