UNITED STATES GOVERNMENT records recently obtained by the American Civil Liberties Union show that state and local police authorities are continuing to trade silence for access to sophisticated phone-tracking technologies loaned out by the Federal Bureau of Investigation. To protect the secrets of the technology, documents show, police departments will routinely agree, if necessary, to drop charges against suspects who've been accused of violent crimes.

The documents, handed over by the FBI under the Freedom of Information Act, include copies of nondisclosure agreements signed by police departments requesting access to portable devices known as cell-site simulators, otherwise known by the generic trademark “Stingray” after an early model developed by L3Harris Technologies. The FBI requires the NDAs to be signed before agreeing to aid police in tracking suspects using the devices. Stipulations in the contracts include withholding information about the devices, they're functionality, and deployment from defendants and their lawyers in the event the cases prove justiciable.

Legal experts at the ACLU, Laura Moraff and Nathan Wessler, say the secrecy requirements interfere with the ability of defendants to challenge the legality of surveillance and keep judges in the dark as to how the cases before their court unfold. “We deserve to know when the government is using invasive surveillance technologies that sweep up information about suspects and bystanders alike," Moraff says. “The FBI needs to stop forcing law enforcement agencies to hide these practices.”

The ACLU obtained the documents after filing a lawsuit in response to a news story published by Gizmodo in 2020. It described a decision at L3Harris to stop selling cell-site simulators directly to local police departments, and how other smaller companies were, in response, moving to fill the vacuum in the market. 

The key function of cell-site simulators is to masquerade as a cell tower in order to identify nearby networked devices. This hack works by weaponizing a power saving feature common to most mobile phones: always ensuring they're connected to the closest cell tower emanating the strongest radio signal. Once the “handshake” between the device and a phone begins, there are a variety of authentication protocols the device must overcome. Tricking modern phones into connecting with the simulator has grown increasingly complicated since the earliest versions of the device were strapped to planes and used to intercept communications on US battlefields.