Mexican authorities haven't contacted Pima County over Nancy Guthrie tip

Somewhere across a border that has long complicated the search for answers, an anonymous voice has claimed to know where Nancy Guthrie rests. Yet the Pima County Sheriff's Department, as of Thursday, has received no word from Mexican authorities to confirm, deny, or even acknowledge the tip — leaving investigators in Arizona suspended between a possible breakthrough and the silence that has defined this case from the beginning. In missing person investigations that cross international lines, even a lead can become a kind of waiting, and waiting its own form of loss.