I don't know about this incident, but I believe Trump is right about one thing. These protests (riots) are well organized and well financed by outsiders. Who they are and where they get the money are things that should have been investigated a long time ago. Seems to me if Trump wanted to do something, he would have his lapdog, Bill Barr, get some kind of investigation going.
Indications are that the protesters and agitators did, indeed come from elsewhere.
It's an old playbook.
We saw this in my childhood in the '60s when local blacks related to my mother that agitators had come into the community to try to incite violence against local whites by local blacks (So. MD). They also related that they'd 'sent them boys back to DC' (where the agitators had come from) because "We ain't never had no problems with our white folks."
Within a couple years, however the FBI was arresting a student at the High School (roughly 25 miles away, but the closest), for running with H.Rap Brown, Stokely Carmichael, and Eldridge Cleaver in connection with the riots in Cambridge, MD. The High School was embroiled in racial unrest (okay, riots) for the two years I went there, until I got a chance to go to a private school.
The play is to send in professional agitators to incite the youth (most malleable--empty minds can be stuffed with all sorts of garbage, especially if no prior morality or sense of history exists, something schools have virtually guaranteed). Anger enables stupidity, hence opportunities for most anything good are destroyed in these fits of anger, especially in their own neighborhoods, often guaranteeing that those opportunities will be lost.
Thus begins the vicious circle of resentment for not having opportunity in the neighborhood, blaming those who will not rebuild there, when they were burned out and no one in their right mind would go back to that environment.
But overall, it is manipulated by outside interests, much as "environmental" lawsuits and protests are brought (with one or two local 'poster children') by outside interests to stop industrial development, force schools to change mascots, whatever, using the system created to address legitimate grievances against America.
(Over 90% of those arrested in conjunction with the Standing Rock DAPL protests were from out of State, protesting a pipeline that did not cross tribal land.)
