For years, police departments have had access to powerful technology that can mimic cellphone towers and allow officers to track suspects' calls and text messages, often scooping up massive amounts of mobile data in the process.
Now, federal and state lawmakers are moving to put tighter restrictions on when and how police can use these powerful tools commonly referred to as Stingrays, which digital rights groups and privacy advocates have long complained can lead to indiscriminate surveillance.
"The Fourth Amendment is very clear that American's should have a right to privacy against warrantless searches," Rep. Blake Farenthold (R) of Texas said Tuesday in a statement announcing his cosponsorship of the Fair Surveillance Act, introduced last month. "Law enforcement and their use of Stingray devices is no exception. We must not allow the breaking down of our civil liberties in [the] name of safety," he said.
The Fair Surveillance Act and the last November's similar Stingray Privacy Act are designed to regulate police use of cell site simulators. Essentially, the bills would require state and local law enforcement agencies to obtain a probable cause warrant before using cell phone tracking technology.
By 2014, 10 states had passed similar legislation. They were joined by California and Washington state last year, according to Jake Lestock, a policy associate at the National Conference of State Legislatures. Stingray legislation is currently pending in Illinois and Rhode Island. And in March, a Maryland appeals court ruled that police in that state need to get a warrant before tracking a suspect's cellphone location.
A Massachusetts bill, drafted by the privacy group Digital Fourth and introduced in January by State Rep. Denise Provost in January, takes a different approach. It would require local law enforcement agencies to get approval from their town’s mayor and council before acquired military-grade equipment, including cell site simulators, from federal agencies.
"If police departments are using Stingrays, it should be after the elected officials of the town have explicitly consented to their use, and after a public hearing giving citizens the chance to weigh in," Alex Marthews, head of Digital Fourth, told Passcode.
Some 65 federal, state, and local agencies in 24 states use cell site simulators to track suspects’ cellphones, according to data collected by the American Civil Liberties Union. However, these devices are also capable of tracking all the cellphones in a given area, or even spying on text messages and phone calls.
A simulator can be as large as a rack-mounted unit that fits inside a police van with an antenna on top, or it can as small as a device that fits in a backpack or even in a user’s hand. The Harris Corporation manufactures the models used by most US law enforcement agencies, according to Ars Technica and The New York Times.
To use the devices, the Times reported, state and local law enforcement agencies must sign a nondisclosure agreement with the Harris Corporation that is overseen by the FBI. Police departments have gone as far as concealing the use of cell site simulators in court documents, according to law enforcement emails obtained by the ACLU.
"In reports or depositions we simply refer to the assistance as 'received information from a confidential source regarding the location of the suspect,' " Sgt. Ken Castro, of the North Point, Fla., police department, wrote in one 2009 e-mail. "To date this has not been challenged."
Last year, the Department of Justice and the Department of Homeland Security issued guidelines requiring their agents to obtain a search warrant based on probable cause before deploying a cell site simulator, except in "exigent circumstances." However, federal agencies that do not fall under the Department of Justice and Department of Homeland Security policies also use cell site simulators — including the Drug Enforcement Agency and the Internal Revenue Service.
The Stingray Privacy Act, introduced by House Oversight and Government Reform Chairman Jason Chaffetz (R) in November, would require all federal, state and local agencies to obtain a warrant before using a cell site simulator and provide for a common set of emergency exceptions. Chaffetz has also opened a committee investigation into use of cell site simulators by federal agencies, which is ongoing.
Legislation from Rep. Hakeem Jeffries (D) doesn’t go quite as far. Rather than requiring all agencies to obtain a warrant, it would simply require state and local agencies to follow a federal agency’s guidelines when they obtain a cell site simulator from that agency. That could potentially leave the door open for local law enforcement to obtain the devices from federal agencies that do not have a warrant requirement.
"The fact that law enforcement agencies, and non-law enforcement agencies such as the IRS, have invested in these devices raises serious questions about who is using this technology and why,” Chaffetz said in a statement. “These questions demonstrate the need for strict guidelines that carry the weight of the law."