On Tuesday night, more protesters marched across U.S. cities to push back against police brutality and the killing of unarmed Black man George Floyd by a white police officer. And overhead, in cities such as Las Vegas, Washington DC, and Portland, the National Guard and law enforcement flew surveillance planes, according to flight data reviewed by Motherboard.
The data shows that flying high-tech and traditionally military-focused aircraft above protesting cities is becoming a norm at this time.
"Military surveillance planes over America's cities are a rare visible indicator of tectonic increases in surveillance quietly underway," John Scott-Railton, a security researcher who has also been tracking some of the surveillance aircraft flights, told Motherboard.
For several hours last night, authorities flew an RC-26B aircraft over Washington DC, making dozens of circles above the city, according to data Motherboard reviewed from ADS-B Exchange, a repository of unfiltered flight data. Authorities also flew a RC-26B over Las Vegas Tuesday night, as spotted by Scott-Railton. The aircraft made repeating circles around different areas of the city, according to flight data reviewed by Motherboard. Tuesday protests in Las Vegas were peaceful according to local media reports, but on Monday police shot and killed one person who was armed. After that, authorities announced the Nevada National Guard would join law enforcement on future protests.
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The RC-26B is a reconnaissance plane carrying infrared and electro-optical cameras, and has been used on counter-narcotic missions and in Iraq and Afghanistan. Authorities also deploy the aircraft for assistance during floods or other disasters.
"The aircraft is uniquely qualified as the only fixed-winged aircraft to have Title 32 authority to conduct domestic surveillance while maintaining the ability to conduct Title 10 missions abroad," a 2018 letter from several members of Congress addressed to the House Armed Services Committee reads.
In this case, the aircraft likely weren't monitoring drug runners, but protesters. As many as 2,000 protesters marched in Washington on Tuesday, according to The Washington Post . The National Guard did not provide a statement in time for publication.
During the RC-26B's flight over DC, a small Cessna 560 previously attributed to the FBI also flew in wide circles around the city, according to the data reviewed by Motherboard. The FBI did not respond to a request for comment, but authorities have previously equipped Cessnas with so-called Dirtboxes, devices that act as fake cell towers to trick phones into connecting and giving up their unique identifying code and track their physical location. While mounted on planes the devices harvest information on a large number of innocent Americans, according to The Wall Street Journal which revealed the practice in 2014.
"Multiple federal agencies are flying surveillance planes over protests, and it's likely that some of these planes are outfitted with a Dirtbox or similar technology," Martin Shelton, principal researcher at Freedom of the Press Foundation told Motherboard. "What this means for protesters and journalists covering these events is that phone numbers, as well as voice calls and text messages, are likely being scooped up for analysis," he added.
Shelton mentioned such devices wouldn't be as effective at intercepting communications of encrypted messaging apps, and protesters could put their phone into airplane mode to disable the device's cell phone signal.
"In 2020, this is what 'Airplane Mode' is for," he said.
Local departments flew their own aircraft over cities during protests as well. The Portland Police Bureau deployed its own Cessna 172N above the city, as noted by consultant Sam Lustgarten, while the New York Police Department flew at least two helicopters over protests there according to the data.
Sergeant Michael Roberts, a public information officer for the Bureau, told Motherboard in an email that "the Portland Police Bureau does have an aircraft which we regularly use for situational awareness. I have nothing else to share at this time."
Scott-Railton also found aircraft flying last night belonging to the Texas Department of Public Safety flying above Houston, and a California Highway Patrol aircraft over Oakland.
A Texas Department of Public Safety spokesperson told Motherboard in an email, "In light of current protests, the Texas Department of Public Safety (DPS) has deployed additional resources across the state, including to Houston, to support local law enforcement. This includes DPS’ air assets, which have been dispatched as needed, to provide assistance in the protection of our communities and assist local law enforcement. Public safety is our top priority, and while we do not discuss specifics related to security measures, the department is committed to working with our law enforcement partners to proactively protect the citizens of Texas." The California Highway Patrol did not respond to a request for comment.
However, it is likely that these are not the only surveillance aircraft flying over Tuesday's protests. Chris Stelmarski from political strategy and media consultant firm MVAR Media tweeted several photos he said he took of aircraft above DC on Tuesday. Not all of these seem to have appeared in the flight data reviewed by Motherboard, suggesting they may have turned off their transponders, the technology that broadcasts their location publicly.
As Motherboard verified last week, U.S. Customs and Border Protection flew an unarmed Predator drone over Minneapolis as protesters marched through the city.
Cooper Quintin, a security researcher and senior staff technologist at the Electronic Frontier Foundation told Motherboard, "It's concerning because we see an unprecedented amount of aerial surveillance of U.S. citizens in multiple cities at once in a clear attempt to chill speech and silence Americans exercising their First Amendment rights."
"We have no way of telling what kind of signals intelligence or other surveillance those planes are carrying but that kind of wartime surveillance on our own citizens should enrage everyone who values freedom," Quintin added.
Update: This piece has been updated with a statement from the Texas Department of Public Safety.
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This article originally appeared on VICE US.