The Native American tribe leading the fight against the Dakota Access oil pipeline said Thursday that an Army Corps of Engineers document shows the agency concluded the pipeline won't unfairly affect tribes before it consulted them.

Standing Rock Sioux officials say the document, which they shared with The Associated Press, bolsters the tribe's claim that the Corps disregarded a federal judge's order to seriously review the pipeline's potential impact on the Standing Rock Sioux and three other Dakotas-based tribes and to not treat the study as a "bureaucratic formality."

"This was a rigged process intended to justify a dangerous and illegal pipeline," Standing Rock Chairman Mike Faith said in a statement to the AP.

The Justice Department did not immediately respond to a request for comment. The Corps has said previously that the four tribes suing to shut down the pipeline that began delivering North Dakota oil to a shipping point in Illinois two years ago have been difficult to work with. And the agency did meet with the tribes before it presented its study findings to U.S. District Judge James Boasberg.

The tribes fear the pipeline could spill oil into the Missouri River and pollute water they rely on for drinking, fishing and religious purposes. Boasberg said the Corps "largely complied" with environmental law when permitting the pipeline, but he also ordered it to further study the pipeline's impact on the tribes.

Boasberg later said he "expects the Corps not to treat (this) as an exercise in filling out the proper paperwork" after the fact, though he also said he thought there was a "serious possibility" that the agency would be able to substantiate its prior conclusions.

The Corps in August 2018 announced that it had completed the work and that it confirmed the agency's earlier determination that the pipeline does not pose a higher risk of adversely affecting minorities. The four tribes have since challenged that conclusion, and the Corps in early February turned over to the tribes the documents it used to make its decision. The records are shielded from the public because some contain pipeline information that might be useful to vandals or terrorists.

One of the documents is a Feb. 4, 2018, draft memo from the Corps to the assistant secretary of the Army for civil works. It states that the agency performed the additional analysis ordered by the judge and "has identified no new information."

"Therefore, decisions made by the (Corps) were in accordance with the law and neither arbitrary nor capricious," the memo states.

The draft memo is dated more than three months before the Corps met with the tribes to hear their concerns.

"How could they conclude that there is 'no new information' before they even talked to us?" Faith said.

The Corps, which has said it had a hard time obtaining information it needed from the tribes, did meet with them in late May 2018.

The official memo it gave Boasberg three months later mirrors the February draft memo in structure but is more detailed and includes two references to having met with tribes. It states that the agency "considered the comments and concerns expressed by the tribes" but that its overall review did not uncover "significant new circumstances or information relevant to environmental concerns."

Standing Rock attorney Jan Hasselman said the tribe believes the February memo shows that the Corps didn't seriously seek tribal input and that its findings were preordained.

"I don't think it's any new fact to anybody that this was a sham from the beginning, but it was a little startling to see it written down so plainly," he said.