Among the Indians, being tried by your own people has a much greater impact on them personally than any punishment by non-tribal members. Being shamed by your people is considered a lot more humiliating than doing some time in a federal jail. While it probably won't happen in this case, some tribes have banished members from their home rez. It is something that is not fully appreciated, understood or known by Anglos as their people have not been here very long. When you're banished from the land on which your people have resided for uncounted years, it affects the person in a profound way that can not happen to an Anglo citizen of this country.
A banished or punished Indian can move to another rez but the word of their actions that caused the punishment in their own tribe will eventually be known and they will be shunned in most cases.
Indian Country has it's own rules that most non-Indians aren't aware of. There will be pressure brought to bear by other tribes but it won't be known to most Anglo citizens. One of my cousins called from Montana to talk to me about it even though we're not tribal members here. The powwow telegraph spreads the word through out Indian Country.