ICE acquisition of surveillance technologies accelerates the loss of public trust in DHS

In January 2026, two American citizens, Renee Good and Alex Pretti, were shot and killed by Department of Homeland Security (DHS) agents. Their deaths occurred during the course of the Immigration and Customs Enforcement (ICE) surge in Minneapolis.

Following the deaths of Good and Pretti, Sens. Mark Warner (D-Va.) and Tim Kaine (D-Va.) “noted that alongside these recent, documented instances of excessive and deadly use of force by DHS immigration enforcement is an unprecedented allocation of funds that may be supporting the inappropriate and unsupervised use of surveillance technology.” They raised concerns that “ICE’s new information collection tools potentially enable DHS to circumvent the constitutional protections provided by the Fourth Amendment – protections guaranteed to all Americans and all persons within our borders.”

My Brookings colleagues Rashawn Ray and Gabriel R. Sanchez have explored several factors contributing to a massive expansion at ICE that has far “outpaced accountability,” undermining the legitimacy of ICE and its immigration enforcement efforts. They identify racial profiling, questionable hiring practices, and lower training standards, among other issues, fueling the credibility crisis at ICE. 

An additional factor to add to their direct analysis of ICE practices is a corresponding failure by Congress to regulate powerful surveillance technologies and information collection practices. That is, when Congress fails to address foreseeable potential abuses enabled by such technologies and regulate them accordingly, it can hardly be surprising that they may be misused. Now, as evidence of the comprehensively aggressive tactics of ICE has become evident across the country, Congress must face the issue of potential ICE abuses of surveillance technology head on and act to curtail them for the protection of the public.

Cell-site simulators: A lesson in governance failure

The Washington Post published a primer on the types of collection practices and surveillance technologies used by ICE, some of which were funded by the “One Big Beautiful Bill Act,” passed in July 2025. The surveillance tools identified by the Washington Post include facial recognition technology, automatic license plate readers, cell-site simulators, phone location databases, and digital forensic tools to hack into cellphones and computers, among other technologies.

Cell-site simulators, often called Stingrays, the trademark of one brand, present a particularly instructive example of governance failure by Congress.

These devices impersonate cell towers and can be used to identify and locate nearby phones in real time. They have the capacity to collect information about cellphones in an entire area, as well as block service, either to all devices in the area or to particular cellphones. They have been used by federal law enforcement since at least the mid-1990s, and ICE acquired cell-site simulators at least as early as 2008. Over the years, cell-site simulators have become a standard if somewhat secretive investigative tool used by both federal and state law enforcement agencies in a variety of investigations, including tax fraud, attempted murder, and to track fugitives.

There is also reporting indicating that cell-site simulators may have been used to collect information during protests, including by ICE. That type of use case, if true, should raise significant concerns, including among members of Congress, in the wake of ICE leadership assertions of  “authority to use all available tools to monitor and investigate anti-ICE protester networks, including U.S. citizens.” This position reflects a disregard for First Amendment rights and suggests an intention by ICE to monitor and investigate U.S. citizens without credible evidence of violations of federal law.

Congress, in its oversight role, has encountered cell-site simulators before. Back in 2015, amid press reports and concerns expressed by civil society and academics over privacy, secrecy, and security issues associated with the technology, the Committee on Oversight and Government Reform in the U.S. House of Representatives began a bipartisan investigation into law enforcement use of cell-site simulators.

During that investigation, the U.S. Department of Justice (DOJ) issued a new policy on cell-site simulators. Until the fall of 2015, DOJ obtained authorization to use a cell-site simulator by seeking a court order under the Pen Register and Trap and Trace Devices statute, which only requires a simple certification that the “information likely to be obtained is relevant to an ongoing criminal investigation,” a much lower standard than a warrant supported by probable cause. Under DOJ’s new guidance, law enforcement, as a matter of policy, would seek a warrant to use cell-site simulators in criminal investigations, absent emergency or exigent circumstances. The U.S. Department of Homeland Security adopted this guidance as well.

To be clear, the DOJ/DHS guidance did not represent the warrant requirement to be a binding legal obligation. The warrant requirement imposed was a policy choice. Without binding case law or federal legislation mandating a warrant requirement, DOJ, DHS, or other federal agencies, to the extent that they have adopted the policy, remain free to change or disregard the policy.

Notably, the Supreme Court has not addressed the question of whether law enforcement use of cell-site simulators to locate or track phones directly in real-time is a Fourth Amendment search requiring a warrant or recognized exception to the warrant requirement. The court explicitly declined to express a view on the constitutionality of warrantless real-time collection of cell-site location information (CSLI) in 2018 when it decided Carpenter v. United States, a case about the government’s compelled disclosure of stored CSLI from telecommunications providers.

As of this writing, no federal circuit court has ruled on the question either. In United States v. Patrick, a 2016 pre-Carpenter case involving the use of a cell-site simulator, the 7th Circuit declined to address questions about whether the “use of a simulator is a search” and if so, “whether a warrant authorizing this method is essential.” The court did note DOJ’s issuance of the new policy indicating it “would ordinarily seek a warrant, plus an order under the pen-register statute,” but that the department had “not conceded that [a warrant was] constitutionally required.” Writing a dissent critical of the majority’s refusal to remand the case for further fact-finding on issues pertaining to the government’s use of the Stingray device, Chief Judge Wood noted that “[w]e know very little about the device, thanks mostly to the government’s refusal to divulge any information about it. Until recently, the government has gone so far as to dismiss cases and withdraw evidence rather than reveal that the technology was used.”

In December 2016, following the issuance of DOJ’s cell-site simulator policy, the House Committee on Oversight and Government Reform issued a bipartisan report entitled “Law Enforcement Use of Cell-Site Simulation Technologies: Privacy Concerns and Recommendations.” The report acknowledges that “[w]hile law enforcement agencies should be able to utilize technology as a tool to help officers be safe and accomplish their missions, absent proper oversight and safeguards, the domestic use of cell-site simulators may well infringe upon the constitutional rights of citizens to be free from unreasonable searches and seizures, as well as the right to free association.”

Given these concerns, the report’s overarching recommendation was that “Congress should pass legislation to establish a clear, nationwide framework for when and how geolocation information can be accessed and used.” In the interim, the report recommended that “[i]ndividual states should enact legislation that governs how law enforcement uses cell-site simulation technology. Legislation should require, with limited exceptions, issuance of a probable cause based warrant prior to law enforcement’s use of these devices,” noting that some states have already done so.

Ten years later, Congress has failed to pass legislation governing law enforcement access to and use of location data, including its use of cell-site simulators. In the absence of federal legislation or more specific Fourth Amendment guidance by federal circuit courts or the Supreme Court, federal agencies remain more or less free to interpret the law and set their own policies regarding the use of cell-site simulators. The history of the cell-site simulator is a useful lens through which to assess the risks associated with other powerful surveillance technologies and collection practices that Congress has failed to regulate.

A growing congressional deficit in the regulation of surveillance technologies

At a time when ICE accountability is severely low and DHS continues an aggressive, if perhaps “quieter,” detention and deportation campaign, the concerns raised by Sens. Warner and Kaine about budgetary expenditures on technologies enabling ICE collection and use of sensitive data about U.S. citizens and noncitizens are extremely valid. They have rightly drawn attention to “DHS’ reported disregard for adhering to the law and its proven ambivalence toward observing and upholding constitutionally-guaranteed freedoms of Americans and noncitizens, including freedom of speech and equal protection under the law,” leaving “little confidence that these new and powerful tools are being used responsibly.”

But it also must be acknowledged that Congress’ failure to regulate powerful surveillance technologies makes it easier for them to be abused. The lack of regulation leaves far more room for interpretation, discretion, and policy choices by law enforcement agencies.

Congress is currently in somewhat of a surveillance regulatory deficit. For example, the Electronic Communications Privacy Act (ECPA), the foundational privacy statute governing law enforcement access to data held by U.S. communications providers, turns 40 this year. When ECPA was passed in 1986, smartphones hadn’t even been invented. Many of ECPA’s rules are now decades out of date.

Sens. Warner and Kaine are rightly focused on an unprecedented allocation of funds that may support “inappropriate and unsupervised use of surveillance technology.” But the use of the word “unsupervised” in this context points to another factor in this dynamic: Congress’ own ongoing failure to provide supervision of surveillance technologies and those agencies that deploy them in the form of regulation. In the current environment, this regulatory failure exacerbates ICE accountability and credibility issues.