Ummm that is a sold sort of. It is more clear now, but is history tribal police couldn’t reinforce the law or even detain non tribal members. After a supreme court ruling and a new federal law tribal place have some power over non-tribal members. But not to necessarily to the extent of other local law enforcement.
They don’t necessarily. Historically they didn’t have jurisdiction over non-tribal members. Now there are some detainment powers, but it is not 100% clear still.