"After the [Dakota Access] pipeline was completed and demonstrators left, North Dakota sued the federal government for more than $38 million — the cost the state claims to have spent on police and other emergency responders, and for property and environmental damage. Central to North Dakota’s complaints are the existence of anti-pipeline camps on federal land managed by the Army Corps of Engineers. The state argues that by failing to enforce trespass laws on that land, the Army Corps allowed the camps to grow to up to 8,000 people and serve as a 'safe haven' for those who participated in illegal activity during protests and caused property damage.
In an effort to prove that the federal government failed to provide sufficient support, attorneys deposed officials leading several law enforcement agencies during the protests. The depositions provide unusually detailed information about the way that federal security agencies intervene in climate and Indigenous movements.
Until the lawsuit, the existence of only one federal informant in the camps was known: Heath Harmon was working as an FBI informant when he entered into a romantic relationship with water protector Red Fawn Fallis. A judge eventually sentenced Fallis to nearly five years in prison after a gun went off when she was tackled by police during a protest. The gun belonged to Harmon."
https://grist.org/indigenous/fbi-informant-standing-rock-protest-court-documents-surveillance/