AUSTIN, Texas — As smartphones revolutionize how people interact with breaking news, internet freedom advocates are warning that “kill switch” technology could shut down this newfound form of expression during times of civil unrest.

Viral video footage of the killings of Alton Sterling and Philando Castile, two black men recently fatally shot by police, triggered nationwide Black Lives Matter protests and renewed a nationwide discussion over the importance of easily accessible video and livestreaming to hold cops accountable.

However, police frequently target those caught filming them, even when courts have repeatedly upheld the right of citizens to do so. Police held Diamond Reynolds, Castille’s fiancee, at gunpoint while she filmed the aftermath of the shooting, and both witnesses to Sterling’s death, Chris LeDay and Abdullah Muflahi, were targeted by police after filming.

But perhaps even more worrisome than police targeting individuals for filming is the idea that the technology which allows witnesses to film and share incidents of brutality could be remotely disabled to stem dissent.

The Department of Homeland Security has a secretive procedure in place to de-activate internet access in the event of an emergency, popularly known as an “internet kill switch.”

Efforts by the Electronic Privacy Information Center to reveal details of the procedure through open records requests were rebuffed first by DHS, then by the Supreme Court, which declined to hear EPIC’s lawsuit in January. The NGO still managed to obtain a heavily redacted copy of the kill switch procedure, which allows the National Coordinating Center for Telecommunications to disrupt internet and cellular access during emergencies at the request of a federal, state or local law enforcement agency.

“The American people are (once again) left in the dark regarding the inner-workings of another dangerous and intrusive government program,” wrote Derrick Broze in January for the Anti-Media. He continued:

“It is only through the hard work of activists and groups like EPIC that we are at least aware of the existence of this program — but knowing bits and pieces about the protocol is not enough. In order to combat such heavy-handed measures, we need to have access to the government’s own documents. Hopefully, there is already a whistleblower preparing to release these details.”

That a kill switch could be used during times of unrest is not a purely theoretical proposition. On Aug. 11, 2011, cellular service was shut down throughout California’s Bay Area Rapid Transit system to prevent protests over the fatal shooting by BART police of Charles Blair Hill on July 3, 2011. Use of internet kill switches by U.S. allies like Egypt or Turkey is also becoming increasingly routine.

Another worrying development is an Apple patent, first filed in 2014 but approved last month, designed to prevent iPhones and other Apple devices from filming at music concerts. But activists and privacy advocates fear the technology won’t be limited to music venues and could easily be abused by police.

Great patent granted to Apple. Won’t be abused/used against citizens, notta chance. https://t.co/y3mfIqh2RR Love innocent-looking schematic. — ✦❋ David Hackett ✺✧ (@sangio_davese) July 10, 2016

“There are definitely situations where the impulse to use this type of technology would be understandable, like performances where artists/backers/venues are looking to control media distribution,” noted Slate’s Lily Hay Newman on June 30. “But as ThinkProgress points out, the ubiquity of portable cameras can help people hold powerful entities accountable for wrongdoing, and it might be tempting for institutions to use this technology to combat transparency.”

And to think @apple is creating software that could potentially allow police to stop your phone from recording. — Aprill is a great skincare blogger, bow down. (@HeyAprill) July 7, 2016

Newman noted that the technology remains purely hypothetical, but cautioned that “this patent could give other people ideas.”

In a July 12 analysis for the Anti-Media, Jake Anderson agreed that the technology is ripe for abuse. He concluded:

“Real-time recording of police transgressions, social media posts that bypass oppressive regimes — these are revolutionary, disruptive technologies. It should come as no surprise the entrenched powers of both dictatorships and democracies are looking for ways to restrict the use of tools that expose government tyranny.”

Watch “How to Film Protests,” a five-part video guide from Witness.org: