Matthew Guariglia, Cooper Quintin, and Dave Maass write:
A new report from news outlet NOTUS shows that at least two Texas counties along the U.S.-Mexico border have purchased a product that would allow law enforcement to track devices that emit Bluetooth signals, including cell phones, smartwatches, wireless earbuds, and car entertainment systems. This incredibly personal model of tracking is the latest level of surveillance infrastructure along the U.S.-Mexico border—where communities are not only exposed to a tremendous amount of constant monitoring, but also serves as a laboratory where law enforcement agencies at all levels of government test new technologies.
The product now being deployed in Texas, called TraffiCatch, can detect wifi and Bluetooth signals in moving cars to track them. Webb County, which includes Laredo, has had TraffiCatch technology since at least 2019, according to GovSpend procurement data. Val Verde County, which includes Del Rio, approved the technology in 2022.
This data collection is possible because all Bluetooth devices regularly broadcast a Bluetooth Device Address. This address can be either a public address or a random address. Public addresses don’t change for the lifetime of the device, making them the easiest to track. Random addresses are more common and have multiple levels of privacy, but for the most part change regularly (this is the case with most modern smartphones and products like AirTags.) Bluetooth products with random addresses would be hard to track for a device that hasn’t paired with them. But if the tracked person is also carrying a Bluetooth device that has a public address, or if tracking devices are placed close to each other so a device is seen multiple times before it changes its address, random addresses could be correlated with that person over long periods of time.
It is unclear whether TraffiCatch is doing this sort of advanced analysis and correlation, and how effective it would be at tracking most modern Bluetooth devices.
According to TraffiCatch’s manufacturer, Jenoptik, this data derived from Bluetooth is also combined with data collected from automated license plate readers, another form of vehicle tracking technology placed along roads and highways by federal, state, and local law enforcement throughout the Texas border. ALPRs are well understood technology for vehicle tracking, but the addition of Bluetooth tracking may allow law enforcement to track individuals even if they are using different vehicles.
Read more at EFF.