Well, I was typing this long description, but I had my dh read it and he said I should just tell you that on the reservation, it is basically a land of lawlessness. I would never feel safe and secure in the information obtained by law enforcement from the res, it is sketchy at best, downright corrupt in reality. I do not deem it a reliable source.
I have lived in close proximity (<10 miles my whole life) to a reservation. Even many of the Indians will tell you this same thing, *of course, this is my personal experience*.
Also, those small isolated towns up around there, and in other parts of AZ have their "own rules" and while the laws are known, and officially enforced, it would drop your jaw to find out things that happen in those towns and courts, just truly unbelievable.
I know this may be an unpopular sentiment, but from the moment this crime took place, it was doomed to a botched investigation, period.