Article continues below advertisementPima County Sheriff Chris Nanos, the man leading the investigation into Nancy Guthrie's disappearance, is facing calls to resign over his professional past."There's this effort now to recall him, where they're gathering signatures," NewsNation correspondent Brian Entin revealed during his YouTube show on Wednesday, March 25, before clarifying "it has nothing to do" with the case of Today star Savannah Guthrie's missing mom.