Regulator's right, I've believed this for a couple of years now. Not necessarily Fox/Bush, but moneyed interests on both sides of the border who stand to lose if we stop the flow of human contraband are the ones behind this.
Hire an investigator to follow the money...starting with the Tucson attorneys who've threatened lawsuits.
I've actually been waiting to hear this, ever since I read one of the EFE reports about Barnett, and they mentioned Fox obliquely referring to him.
But I agree that there are lot of people, especially those who are linked to Mexican crime families in Sonora, who would be working to get him gone, and they may have their hooks into the PHX office of the FBI. If that's true (why not? they've corrupted plenty of the Customs people at the border), it's terrifying. But believable.