Illinois has now joined the ever-expanding list of states that require law enforcement officials to explicitly seek court approval before deploying cell-site simulators , which can locate and track a person’s cell phone without their knowledge.

On Friday, Gov. Bruce Rauner (R) signed the “Citizen Privacy Protection Act” into law, which will take effect on January 1, 2017.

The application to the court “must include a description of the nature and capabilities of the cell site simulator device to be used and the manner and method of its deployment, including whether the cell site simulator device will obtain data from non-target communications devices.” The law also requires the “immediate deletion” of non-target data obtained via the cell-site simulator.

Cell-site simulators—known colloquially as stingrays—can be used to determine a mobile phone’s location by spoofing a cell tower. In some cases, stingrays can intercept calls and text messages. Once deployed, the devices intercept data from a target phone along with information from other phones within the vicinity. At times, police have falsely claimed the use of a confidential informant when they have actually deployed these particularly sweeping and intrusive surveillance tools.

In recent years, stingray use has come under increasing scrutiny. Several states, including California Minnesota , and Utah , now mandate that a warrant be issued for use of the devices. Last year, the Department of Homeland Security and the Department of Justice also imposed new policies that require a warrant for stingray use in most cases.

In the Land of Lincoln, a Chicago-based privacy activist has a pending lawsuit against the Chicago Police Department as a way to force the agency to open up about how its stingray has been used in the nation's third-largest city.

Earlier this month, a federal judge in New York ruled that the government could not warrantlessly use its stingray to locate a drug suspect asleep in his apartment. As a result of the ruling, the judge suppressed the evidence found in the man’s bedroom—a kilogram of cocaine—likely ending the case.

“Given the prevalence of these devices and our reliance on the technology daily in today’s society, cell site simulator technology [is] too powerful to remain unregulated,” Khadine Bennett of the American Civil Liberties Union of Illinois said in a statement. “The federal government has adopted modest guidelines similar to those enacted today. If the restrictions are good enough for the FBI, they should be workable for local law enforcement in Illinois.”