How Police Track Protesters | Police Surveillance

Over the last three weeks, hundreds of thousands of Americans have gathered across the country to protest police violence and racial injustice in the wake of George Floyd’s death. But here’s something to be aware of: If you’re attending a protest, there’s a good chance the police in your city can—and will—know you’re there.

From body cameras to cell-site simulators, license plate readers, social media monitoring tools, and drones, the police have eyes on the ground, road, subways, internet, and practically any protesting site you can imagine.

In the past two decades, police departments around the country have become a hot target for commercial technology companies. Firms like Amazon and Axon market products to police departments that promise to make their jobs easier, better, and more effective. But this tech often results in poor policing, says Dave Maass, senior investigative researcher for the Electronic Frontier Foundation (EFF).

“Police departments are doing less outreach, less legwork, and fewer investigations,” Maass tells Popular Mechanics. “Instead, they’re relying on untested technology that can result in more abuse and corruption. Not to mention, it’s a waste of taxpayer money.”

Commercial companies offer kickbacks to police departments, which sometimes act as business development engines to increase customer purchases or usage. Amazon, for example, enrolled police departments to promote adoption of their Ring cameras in communities around the U.S.

Amazon also handed out many free Ring units to police departments at police conferences. According to Maass, officers received five free Rings for attending one party; that’s roughly $1,000 in free products. Additionally, Amazon gave free devices to police for every 20 people they convinced to use the Ring app. These marketing tactics may have led to an over-investment in, overt preference for, or unnecessary adoption of surveillance marketing tools.

It’s largely unclear how much police departments are spending on surveillance technology. They don’t always report what they use, how much it costs, and how it’s being implemented. And while police departments claim this secrecy is necessary due to copyright infringement and other trade secret laws, it may be putting your privacy at risk.

What Do the Police Use for Surveillance at Protests?

Police have a variety of tools at their disposal that they can deploy to monitor who’s attending a protest, how they’re moving, and who to hold accountable if something goes wrong.

Automated License Plate Readers (ALPRs)

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Automated License Plate Reader (ALPR)

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How they work: These computer-controlled camera systems are used to capture and time- and location-stamp license plate numbers. This data, which includes a photo of the car and driver (if it’s moving) is stored in a central database. The information can be used to track those who attended, parked near, or left an event like a protest.

How to spot them: ALPRs come in a wide array of shapes and sizes. They generally look like clunky boxes affixed to streetlights, street poles, mobile units, and trailers.

How to protect yourself: If you live in a state where you’re not required to have a front license plate, remove it. And if you have the option, don’t drive your personal car to protests. Instead, consider walking or using public transportation.

Body-Worn Cameras

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Body-Worn Camera

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How they work: Police officers wear these cameras on their bodies to record events and document the use of force. But the cameras can also record and document people in any situation where a cop is present. If used en masse and with facial recognition software, this could impinge on First and Fourth amendment rights. Additionally, early research shows body cameras are largely ineffective at curbing the use of force.

How to spot them: You can generally look for a box-shaped device worn on the chest of a police officer. However, police officers can also hide them underneath their vests, sometimes covertly, in a “button-hole” on their shirts.

How to protect yourself: The best way to evade being captured by a body-worn camera is to stay out of the line of sight of police officers. If you’re near an officer, make sure you don’t have any visible identifying features; wear a mask and a hat to block the camera’s ability to identify you. But you can also use body cameras in your defense if an officer uses excessive action or otherwise behaves inappropriately.

Cell-Site Simulators (IMSI Catchers, Stingrays, or Dirtboxes)

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Cell-site simulator.

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How they work: These tools pretend to be legitimate cell phone towers and trick cellular devices into connecting to them. Once connected, they can identify International Mobile Subscriber IDs and determine who was or wasn’t at a protest. The devices gather metadata and content of phone calls, personally identifying information, and data usage, and are used in at least 24 states.

How to spot them: The SITCH project has open-source software that can be used to detect cell-site simulators. can help show where verified cell towers are. Correlating the two data sources could help expose when cell-site simulators are being used. And SeaGlass is a hardware project out of the University of Washington that helps to identify IMSI catchers in use.

How to protect yourself: Short of building a device to help identify stringrays along and around a protest, simply put your phone into airplane mode.



Police drone.

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How they work: Drones can have high-definition, live-feed video cameras, thermal infrared video cameras, heat sensors, automated license plate readers, and radar, which are used to track, monitor, and watch groups. They can also include cell phone interception technology and back-end software tools like license plate readers, face recognition, and GPS trackers.

How to spot them: Drones vary in size from tiny UAVs to large-scale military drones. Generally, look up and you may be able to spot them. However, know that media and activists also use drones to report on and track police action during protests.

How to protect yourself: If you want to determine if drones are being used, you can consider using acoustic sensors, radio frequency analyzers, and optical sensors. But that’s probably not an option for most people. In that case, use the same techniques to avoid facial recognition or FLIR technology that we recommend in other sections.

Facial Recognition Software

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Facial recognition software.


How it works: This software can be used in conjunction with any camera to identify people in photos, videos, and real life. It can also be used during the booking and trial processes in many police departments.

How to spot it: Any camera you encounter at a protest may have facial recognition software installed. It’s better to assume it does than to assume it doesn’t.

How to protect yourself: You can find out if your local police department is using facial recognition software through this interactive map. To avoid being detected at a protest, cover your face with a mask and wear a brimmed hat.

Forward-Looking Infrared Cameras (FLIR)

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FLIR camera.


How they work: These cameras can register a person’s body temperature and help find people when conditions make it so they otherwise wouldn’t be seen.

How to spot them: FLIRs are handheld or mounted on a car, rifle, or helmet, and can also be used with drones or UAVs. They can often be extremely difficult to spot.

How to protect yourself: Hide behind a source that blocks heat signatures and minimize your skin exposure. Wearing long sleeves can reduce your visibility by up to 15 percent. Additionally, the best times of the day to be outside are at sunrise and sunset, when thermal imaging capture is less effective.

Mobile Surveillance Towers (MSTs)

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Mobile surveillance tower.

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How they work: These mobile tower units are often equipped with ALPR technology, speakers, lights, and video cameras and are used to monitor events from a “birds-eye view.”

How to spot them: These are easy to spot as they’re large, police-manned towers in public spaces.

How to protect yourself: The bigger threats from MSTs are video and FLIR capture. Refer to those sections for how to best evade detection.

Social Media Monitoring

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How it works: Police use hashtags, public and private accounts, digital message boards, and standard social platforms to monitor protesters at an event. This can be done by actual people or algorithms that monitor and farm data.

How to spot it: Review this document, which will help you determine if you’re talking to a bot, and otherwise assume that all public posted social information associated with a hashtag that’s being used to help protestors is also being used to help the police.

How to protect yourself: Be mindful of whether or not you’re talking to a bot, determine if you want to privatize or anonymize your online presence, and take the platform-appropriate steps to do so. You may also want to consider refraining from posting to social media from protests until after you’ve left. This protects your privacy and the privacy of those around you.

How to Stay Safe Before, During, and After a Protest

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Police surveillance technology can be frightening and may dissuade you from attending a protest. But before you give up your democratic duty and constitutional right to gather and activate for change, there are further actions you can take to make yourself safe.

Before the Protest

  • Consult the EFF’s Surveillance Self-Defense Guide.
  • Enable full-encryption on your cellular devices to ensure your data isn’t accessible if it lands in the hands of police.
  • Remove fingerprint lock and FaceID.
  • Consider using a fully encrypted social messaging service instead of text messaging.
  • Back up your data in the event your phone is confiscated.
  • Dress for evasion or anonymity: Cover up tattoos, wear non-traceable clothing, and wear a mask. (You should be doing this anyway in the age of COVID-19, but it also helps to reduce your chances of being identified by FLIR, monitoring cameras, or other means).
  • Make alternate transportation plans. ALPRs will most likely track your car and be able to identify you at a protest, but public transportation will also have a record of you depending on what form of payment you use.
  • Know the phone number of legal representation in your area.

    During the Protest

    • Put your phone on airplane mode. This will reduce the chances of connecting to a cell-site simulator or otherwise being tracked.
    • Don’t unlock your phone if you don’t have to. An unlocked phone is fair game for police officers.
    • Scrub the meta-data off of your photos to reduce the likelihood of them being incriminating evidence.
    • Protect your community. Be careful of where you post photos and who is in those photos.
    • You’re not required to give your password or hand over a cell phone to anyone. Ask if you’re being detained; if the answer is no, then you can walk away.

      What to Do If You’re Arrested at a Protest

      • Call a lawyer. If you don’t have a number for one, ask fellow protestors. “Remember to stay silent,” Henna Kahn, a staff attorney in the criminal defense practice for Neighborhood Defender Service of Harlem, tells Popular Mechanics. “And don’t consent to a search of your phone.”
      • Consider giving your phone to a friend instead of bringing it with you to the precinct office. This reduces the risk that police can use it against you.
      • Refuse to unlock your device if asked. You’re not required to unlock your phone, and you should instead ask for a lawyer to be present.
      • Police can voucher your phone as arrest evidence if they think there’s evidence of a crime on the phone. Otherwise, they may voucher your phone to keep it safe. Assuming the latter, you can get your phone back when released. Assuming the former, you won’t get your phone back until the end of the criminal case.

        “People have a first amendment right to protest,” says Khan. “It’s troubling that the government is conducting this level of surveillance. It’s important, now more than ever, that people know their rights.”

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        So the Police Have Your Data. Now What?

        “I worry about the transparency—or lack thereof—of the surveillance, as well as how the data is used and regulated more than the kinds of technologies,” Andrea Little Limbago, VP of Research for Interos, tells Popular Mechanics.

        The technology is merely the acquisition method, and it’s concerning to think about what happens to the data after it’s been collected. For example, right now, data collected from ALPRs and other sources is often sold to third parties, who then resell that data to insurance providers, banks, and credit monitors. Vigilant Solutions and ELSAG are the largest ALPR vendors of this information, and there’s little you can do to request the removal of your information.

        “It’s important, now more than ever, that people know their rights.”

        While public protest over data usage and facial recognition software has made some progress, it may not be the right approach. Recently IBM, Microsoft, and Amazon agreed to stop (or temporarily halt) selling their products to police departments.

        “What seems to be missing from that conversation is that the technology exists and will continue to be developed,” Limbago says. “And while American multinational corporations seem to be stepping back from that research, techno-authoritarian states will continue to refine their surveillance states, and companies like Clearview AI will continue designing facial recognition tools for the police, with much less oversight or media scrutiny.” This is dangerous territory.

        What we need is not less-qualified companies creating software, but more public engagement in the rules guiding the technologies being used in our society. Police officers are city employees. Cities are reflections of our society. The public should determine what police officers use—and do not use—to surveil them.

        The Community Control Over Police Surveillance (CCOPS) passes CCOPS laws that ensure residents are empowered to decide if and how surveillance technologies are used, through a process that maximizes the public’s influence over those decisions. Not only do CCOPS laws require the public to be informed about technology, but they also actively push police departments to defend the interest in, purchase of, and adoption of new technologies.

        By participating in and pushing for this legislation, protestors and citizens can change the dialogue; we shouldn’t need to evade police detection to protest unless we’re doing something wrong. With greater transparency, legislation, and activism to create accountability and transparency, this article wouldn’t even need to exist.

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