[Destro]

I tend to be drawn to the theory that the cannibalism seen in "Anastazi" sites was an act of political terror by Mexican origin overlords - probably the pre-Columbian Aztecs. A way to keep a people that occupied a vital trade route in line without the need to garrison a large occupation force - the Aztecs would raid these people every year - extract tribute in the form of goods and human sacrifices, carry out acts of terror like cannabalisim of the tribe's important people and leave.

[Betis70]

That is one theory, though the Aztecs were much later than these instances of cannibalism. There isn't a whole lot of evidence of contact with Central Mexico and the US SW other than a few bells and tropical feathers, and some Arizona/New Mexico turquoise in central mexico.