At the height of the movement to stop the Dakota Access Pipeline’s construction last fall, the Federal Aviation Administration imposed a rare “temporary flight restriction,” also known as a no-fly zone, covering nearly 154 square miles of airspace above the pipeline resistance. The no-fly zone — a response to the activities of indigenous drone pilots, whose aerial videos documenting the struggle at Standing Rock drew large social media followings — was approved from October 25 to November 4 in 2016 and renewed twice to cover a smaller area, remaining in effect until December 13.

Documents obtained via open records requests, as well as material from court cases, reveal new details about how the FAA and state agencies helped police and private security companies wrest control of the airspace above the NoDAPL resistance from indigenous water protectors.

Following the flight ban, the media was no longer permitted to use aircraft to cover the events without undergoing a review process. According to the FAA’s no-fly order, “Only relief aircraft ops under direction of North Dakota Tactical Operations Center [were] authorized in the airspace.” Meanwhile, aircraft operated by Dakota Access Pipeline security officials continued to fly over the area to conduct surveillance. The FAA confirmed to The Intercept that the flights would have been legal only if the private security aircraft were participating in a law enforcement action. Prosecutors have used footage from those flights as evidence in felony cases brought against pipeline opponents, displaying an unusual and troubling partnership between the private security operatives and law enforcement.

As The Intercept has previously reported, pipeline builder Energy Transfer Partners hired the shadowy mercenary firm TigerSwan in September 2016 to oversee its security operation. TigerSwan moved quickly to establish a collaborative relationship with law enforcement. The Intercept received more than 100 leaked documents from a TigerSwan contractor describing those efforts in detail, along with DAPL security’s broader strategy of using aerial surveillance, infiltration, and social media monitoring to counter the water protector movement. TigerSwan, which began as a military and State Department contractor, frequently used the language of counterterrorism to inflate threat assessments, at times comparing the water protectors to jihadi insurgents.

Court documents confirm that DAPL security personnel were coordinating their flights with state agencies. In a police report concerning a highly militarized October 27 police raid during the no-fly period, Lt. Cody Trom of the Bismarck Police Department wrote that a team of officers assigned to clear protesters from a bridge at County Road 134 included a “DAPL air asset.” A spokesperson for the Morton County Sheriff’s Department, one of the agencies leading the police response at Standing Rock, told The Intercept, “DAPL was not deputized.” The spokesperson did confirm, however, that law enforcement personnel were present on DAPL aircraft. “During no-fly zone periods, a law enforcement officer was always on board the helicopter. The helicopter was flown by a private contractor, and a law enforcement officer accompanied him to conduct aerial surveillance.”

As the temporary flight restriction went into effect, at least one DAPL security aircraft circled the airspace above the police raid on October 27, photographing water protectors and coordinating with police.

The DAPL photos from that day have become key evidence in a federal felony case accusing five indigenous men of helping set fire to barricades on North Dakota County Road 134. If convicted, they each face a mandatory minimum sentence of 10 years in prison.

In a January 24 affidavit and in a later court hearing, Special Agent Derek Hill of the Bureau of Alcohol, Tobacco, Firearms and Explosives described how he identified at least two of the defendants, Michael Markus and Brennon Nastacio. “While law enforcement was conducting their operation, a helicopter that was being utilized by the Dakota Access Pipeline was monitoring the situation from the air,” Hill wrote in the affidavit. “A passenger in the helicopter was utilizing a digital camera to document the operation, and these digital photos were provided to law enforcement.”

“From a constitutional standpoint, landowners and others who have property rights have every right to show the police evidence that someone has trespassed on their land,” says Lee Rowland, a senior staff attorney with the ACLU’s Speech, Privacy, and Technology Project. “But if this instead amounted to deputizing a private company to take aerial surveillance of protesters on public property, including streets, and snitch on them to the police, that’s deeply problematic.”

According to water protectors, a DAPL helicopter frequently strayed from Dakota Access property. “The yellow helicopter that we’d identified as being DAPL’s flew to the south of DAPL property lots of times on October 27,” says Dallas Goldtooth of the Indigenous Environmental Network, who often filmed and livestreamed from the water protector camps in North Dakota.

A spokesperson for the North Dakota Department of Emergency Services did not respond to a request for comment. Vicki Granado, a spokesperson for Energy Transfer Partners, told the Intercept, “We are thankful for the professionalism and the services provided by all the law enforcement teams that were on the ground in North Dakota that ensured the safety not only of our employees, but the safety of those who live and work in the Mandan area. Beyond that, we do not comment on our security programs.” TigerSwan did not respond to inquiries.

A spokesperson for the FAA noted, “The Federal Aviation Administration carefully considers requests from law enforcement and other entities before establishing Temporary Flight Restrictions (TFR) in U.S. airspace. The TFR over the pipeline protest was approved to ensure the safety of aircraft in support of law enforcement and the safety of people on the ground.”

The FAA spokesperson noted that the flight restriction offered provisions for media to operate aircraft as long as they complied with FAA rules around licensing and safety, and coordinated with the agency before flying. The agency did not respond to questions about how many media operators obtained waivers, stating, “We did not deny any requests from media who met those requirements.” One drone pilot, Rob Levine, eventually obtained a media waiver, but only in a small segment of the restriction zone.