Nevada has signed onto a contract for software that privacy experts say could allow police to track cellphone location information over long periods without obtaining a warrant, a shift that civil liberties advocates argue could undermine constitutional protections around search and seizure.
The Nevada Department of Public Safety adopted the Fog Data Science tool in January through a state contract, and the agreement authorizes investigators to run more than 250 queries each month, according to company documents cited in reporting and interviews with digital-rights experts. The tool is designed to pull information from smartphone apps and help state investigators identify where mobile devices are located.
The software is also described in privacy-related reporting as enabling officers to see “patterns of life,” a capability that could be used to infer where and when people work and live, where they travel, and with whom they associate. Privacy experts said that long-range tracking raises heightened concerns because cellphone location data can reveal extensive details about everyday movement.
Fog Data Science has said its data is made anonymous and “linked to devices … not people,” while the company also says the tool can help access information that “would otherwise remain hidden.” The company provides an opt-out tool on its website, according to reporting.
Civil liberties and privacy advocates said the central issue is the warrant process. Traditionally, police must obtain a warrant from a judge to access cellphone location information, and advocates argued that the Fog system could be used in a way that bypasses that requirement. Jacob Valentine, a staff attorney at the American Civil Liberties Union of Nevada, called the contract “alarming,” saying the state is pursuing attempts to track people “at all times and circumvent the warrant process.”
Concerns have also surfaced as Nevada lawmakers and officials debate other surveillance technologies. In March, Democratic Nevada Attorney General Aaron Ford signed onto a letter calling on Congress to regulate data broker information, while state lawmakers have expressed concerns about guardrails for automated license plate readers that are present across major Nevada cities.
In a response to questions, Nevada Department of Public Safety officials said they will use the tool to enhance information collection and threat-based analysis and to assist with criminal and terrorism-based investigations. Officials said they were “unable to provide specific tactical information” for operational security, and a spokesperson said the agency’s “use of the product follows agency procedures and internal controls for computer access, confidentiality of information and case management.”
Privacy experts said the system relies on advertising identifiers tied to devices, and that those identifiers can be traced back to locations such as homes and workplaces. In an explanation of Fog’s operations cited in reporting, a privacy-focused group described two types of searches: one that lets an officer look up a specified device and another that returns location signals in a given area.
Beryl Lipton, a researcher at the Electronic Frontier Foundation, said the contract’s query volume is a key concern. “You can cover a lot of ground with 250 queries,” Lipton said, arguing that investigators could use the tool to “vacuum up” information about people who are not connected to a case. She also described the broader pattern of low-cost surveillance offerings and said deals like these can sometimes be tied to federal funding mechanisms.
John Piro, a public defender with the Clark County Public Defender’s Office, said the technology’s use is “unconstitutional,” arguing that even if people share location data through apps they use, it does not amount to consent for the government to access all of their movements. Piro pointed to the U.S. Supreme Court’s 2018 decision in Carpenter v. United States, which held that gathering detailed cell location data constitutes a search under the Fourth Amendment and requires a warrant.
Reporting also cited past litigation in Nevada and related cases elsewhere about mass access to location data. The cluster’s reporting referenced a 2020 incident in which California police obtained cell tower location information for more than 1,600 people after charging a Nevada resident with murder-for-hire, and said a Nevada federal court judge ruled the officers’ collection of large quantities of private personal data from cell towers was unconstitutional, while also finding the officers acted in good faith.
Other Nevada agencies have also used different forms of surveillance technology. The reporting said the Las Vegas Metropolitan Police Department acquired a cell-site simulator in 2013 that mimics cellphone towers and can sweep up signals from entire areas to track individuals, with some models capable of intercepting texts and calls, while police have not released detailed information about the technology.
Lipton and Piro said accountability mechanisms remain unclear, and they warned that the same capabilities used in investigations could be applied against everyday people, including those exercising First Amendment rights such as protest activity. Lipton said it would be easier for officers to search an area where a protest occurred and trace cell data back to home locations if there are not clear audit safeguards.