His adoptive mother was a member of the Tribe; the boy's 31-year-old father was not per other local news reports. Only those 1/4 Pascua Yaqui are accepted to tribal membership. They did live on the reservation. Neighbors spoke of their "surprise" of this crime. I wonder any other charges, if any, will be brought forward since there is another child in the home. The tribal website includes these videos on their prosecutorial and a rather recent document on the tribe's page for their attorney general.
https://www.pascuayaqui-nsn.gov/index.php/features/prosecutor-s-office
https://www.pascuayaqui-nsn.gov/index.php/features/attorney-general
https://www.pascuayaqui-nsn.gov/index.php/features/public-defender
I've never heard of this not-so-USA Native American (continental) tribe that apparently received legal asylum in the United States of America nor extreme Catholic fundamentalists, except of course, Pope Clement's purge of heretic Templars, but I was under the understanding that it was forbidden for parishioners and untrained clergy to perform exorcisms. Neither am I familiar with tribal religion, heritage, or culture, but a quick check of the Wiki https://en.wikipedia.org/wiki/Pascua_Yaqui_Tribe gives some information while their tribal cultural page about this tribe gives another interesting take that may border on Catholic extremism blended with tribal beliefs and a heritage that points to Mexican roots. https://www.pascuayaqui-nsn.gov/index.php/culture-home
A modern local bar band on FB is indeed called, "The Demons." The band actually gives up "working" during Lent per posts. So, it does seem these indigenous tribe embraced strongly blended native and Catholic beliefs.
Another page sites this tribe's ancestral character: https://mexican-pearls.myshopify.com/pages/a-small-tribute-to-the-yaqui-yoeme-indian-nation
My heartbroken condolences to the family and friends of this little innocent.