Cook County prosecutors are being sued to provide records of criminal cases that have involved the use of covert cellphone tracking systems — devices that have drawn the scrutiny of the U.S. Senate and privacy activists.

Freddy Martinez, a Chicago-area resident in the software industry, brought the lawsuit Thursday in Cook County Circuit Court, saying the state’s attorney’s office didn’t respond to his efforts to obtain the information through the state’s Freedom of Information Act.

The lawsuit, filed by attorney Matthew Topic of the law firm Loevy & Loevy, follows a similar one Martinez brought against the Chicago Police Department. So far, the police have revealed to Martinez that they spent hundreds of thousands of dollars since 2005 on cell-site simulators made by the Harris Corp. in Florida. The devices, with names like StingRay and KingFish, capture cellphone signals.

But the police department is resisting Martinez’s request for documents spelling out exactly how the devices are used. The city has been billed more than $120,000 in legal fees to fight Martinez’s lawsuit.

Police departments in other states have been compelled to reveal in court that they use the devices to locate cellphones. Those uses range from finding a kidnapping victim or missing person to tracking a criminal.

But privacy activists are concerned that police are also using the devices to track protesters in violation of their free-speech rights. They also bristle that the devices gather the phone data of innocent citizens and police targets alike.

The U.S. Senate Judiciary Committee has asked the Justice Department how the devices are used by federal law enforcement agencies and whether the devices can monitor texts and phone calls, as well as phones’ location information. A spokesman for Sen. Dick Durbin (D-Ill.) said the senator, a member of the committee, supports the inquiry.

Martinez’s latest lawsuit accuses the Cook County state’s attorney’s office of presenting evidence against criminal defendants that was obtained using cell site simulators without obtaining a warrant based on a showing of probable cause. The lawsuit also alleges the Chicago Police Department provided prosecutors with evidence from cell-site simulators based on court orders that didn’t specifically say they were asking to use such a device.

In January, the state’s attorney’s office told Topic the office doesn’t have a list of cases in which StingRay equipment or other cell-site simulators were used to obtain evidence.

“And, unless an issue arose at trial in which proof needed to be adduced to show the source of some particular evidence, a [prosecutor] who tried a case in which some law enforcement officials obtained information from a cell site simulator would likely not know whether any evidence in that case was obtained through a StingRay,” the office said in a written response to Topic.

The state’s attorney’s office also said revealing documents about the use of the devices in terrorist or drug cases could compromise investigations. Finally, the office said a search for such records would be “overly burdensome.”

CCSAO Phone Lawsuit