By of the

Two privacy organizations have called out Milwaukee police for secretly tracking the precise locations of cellphone users without getting search warrants.

Law enforcement officials are using devices, called Stingrays, that simulate a cellphone tower. They can find phones even when they're not in use, or when they have location privacy enabled. Originally developed for national security, they have become a powerful tool for local police who promise the FBI they won't acknowledge having Stingrays to anyone else, including judges who might ask what led to a defendant's arrest.

The ACLU and the Electronic Frontier Foundation, a California nonprofit founded in 1990 that advocates for digital freedom and privacy, say the practice, which pulls in all phones in the vicinity, not just the targeted number, amounts to unreasonable search and seizure under the Fourth Amendment.

"It makes it a whole lot easier to use it if no one's asking questions," said Nate Wessler of the ACLU's privacy project in New York. "It's convenient (for law enforcement) but inappropriate."

The two groups have filed a friend of the court brief in the case of Damian Patrick, 27. Police originally claimed only that they had "obtained information" from an "unknown source" that had pointed them to Patrick's location, in a car where a gun was found on the floor in front of him.

It later came out that police simply tracked Patrick's phone in real time with the help of his service provider and probably a Stingray.

"The requirement that police obtain a warrant ensures that judges can prevent the police from undertaking unjustified fishing expeditions that can reveal intimate details about a person's activities, associations and beliefs," the groups' brief says.

They also argue police should have revealed that they tracked Patrick's phone as part of discovery in the case. The truth didn't come out until months later, during a hearing on Patrick's motion to suppress evidence.

Milwaukee police did not return a request for comment on its use of Stingrays.

The department, like the more than 50 other state and local law agencies who have them or similar devices, must sign a nondisclosure agreement with the FBI that prohibits mention of the technology to anyone — even prosecutors, defense lawyers and judges — without written FBI permission.

The ACLU says records show that from late 2010 to August 2015, Milwaukee police used the Stingray in 579 cases, from homicides and sexual assaults to kidnappings and robberies — and to track down witnesses who didn't appear at trials.

As of April 2014, Wisconsin law requires police to get a search warrant before using the devices, which imitate cellular towers used by wireless providers such as Sprint and Verizon. It forces any mobile phone nearby to identify itself, allowing police to capture data from their targeted phone, as well as all other phones within range.

In October 2013, a task force was rounding up people wanted for violating probation. Police got an order from a state judge for Sprint data about Patrick's phone. A service provider can place a phone in a general area, and then a Stingray, often inside a vehicle, can pinpoint the exact location of the phone, even inside buildings.

On Oct. 28, 2013, the same day the Milwaukee police Stingray log shows its use for a fugitive roundup, Patrick was found in a car, along with a gun.

It wasn't until a February 2014 hearing on his motion to suppress the evidence that it was revealed police had not in fact acted on an informant's tip to find Patrick, but had actually tracked his location by his cellphone.

Prosecutors agree a warrant to track someone's cellphone needs to be based on probable cause, but they argue that the state court judge's order to get Sprint's records of Patrick's calls was the functional equivalent.

Patrick made a conditional guilty plea, was sentenced to 57 months and then appealed the denial of his suppression motion.

To get a judge to order a phone company to reveal records, investigators basically need to say it would be helpful to an investigation, a much lower standard than what investigators would have to show as probable cause required for a search warrant: that evidence of a specific crime exists at a specific location.

The thought had been that cellphone customers don't have an expectation of privacy in the information because they willingly share it with a provider. But privacy advocates say as cellphones grow increasingly powerful and essential to many users, that view is changing.

Since 2013, about a dozen states have adopted requirements for search warrants to track cellphones, and others have introduced similar legislation.

Wessler of the ACLU noted that Wisconsin's law says a warrant should be granted if investigators show the phone tracking will provide "information relevant to an ongoing criminal investigation," a lower standard than usually required for a search warrant.

Some federal agencies have adopted that as a policy, but there is no statutory requirement. Patrick's attorney and the ACLU want the 7th U.S. Circuit Court of Appeals to definitely say one way or the other if the practice triggers Fourth Amendment protections. Other circuits have taken differing views, meaning the question could ultimately land with the U.S. Supreme Court.

Other cities review Stingray cases

In other cities, revelation of the extent of Stingray use, and the extent to which that use was purposely hidden or obscured, has led public defenders to seek reviews of cases where it might have been challenged.

Randy Kraft, a spokesman for Wisconsin's State Public Defender's office said it "is exploring methods to identify cases in which Stingray and similar technology is used."

"In addition, the SPD is considering whether a policy change would be appropriate, and we will reach out to the Legislature if that route becomes necessary."

In some instances nationally, prosecutors have dismissed cases rather than reveal the use of Stingrays when pressed by defense attorney or judges about the sources of information. That has happened even though there has been increasing coverage of the use of Stingrays over the past two or three years, and it's no secret that police around most of the country use the technology.

In fact, the nondisclosure agreement specifically prohibits Stingray users from disclosing Stingray use "in response to court ordered disclosure."

Milwaukee County Circuit Judge David Borowski, who spent years in the felony division, said he didn't recall a case where live cellphone tracking was suspected or revealed, but said he doesn't like the idea that it may have been going on and kept from him.

"Law enforcement needs to be candid and honest with courts and judges," he said.