After reports first surfaced in March, the U.S. Secret Service appears to have reached a deal with Virginia-based Babel Street for the use of its Locate X software, which would give the federal law enforcement agency access to cellphone-location data, Vice News' Motherboard reported Monday.

The Locate X tool is able to collect data from apps used on smart devices to track the date and time users were in a certain location. Motherboard was able to confirm the Secret Service’s use of the program through a Freedom of Information Act filing, revealing a contract valid from 2017-18. Sources close to the matter have said U.S. Customs and Border Patrol and Immigration and Customs Enforcement used Locate X, but this has not been confirmed.

The ability to access personal data from Americans without a warrant has raised numerous privacy and security concerns and drawn criticism from citizens, politicians, and activist groups alike. An investigation of Venntel, a similar data tracking firm that was believed to have worked with the Department of Homeland Security, was initiated by the House of Representatives in June.

The data obtained through Locate X is generally collected to be shared with commercial and non-governmental organizations, which are known to share with government groups like the Secret Service without a warrant. The Secret Service was said to be using Locate X to track down users of credit card skimmers at gas stations, but Motherboard could not confirm this or any other use cases in its recent report.

“It is clear that multiple federal agencies have turned to purchasing Americans’ data to buy their way around Americans’ Fourth Amendment Rights,” Sen. Ron Wyden told Motherboard. “I’m drafting legislation to close this loophole, and ensure the Fourth Amendment isn’t for sale.”

The Motherboard report comes as concerns grow about the growth of mass government surveillance under benevolent guises. Similar issues have been raised with regard to the use of surveillance tools to conduct contact tracing amid the coronavirus pandemic.

While vital now for the containment of a deadly disease, privacy advocates say they provide governments with a framework for intrusive and unwarranted mass surveillance of their citizens. While the Secret Service may have employed Locate X to apprehend criminals, there are concerns that it could be used to track others.

Members of the US Secret Service take up position at the White House
Members of the US Secret Service take up position at the White House AFP / Brendan Smialowski