Secret StingRays were used to investigate murders and kidnappings

In 2010, a reputed gang member beat an Irish exchange student into a coma with a baseball bat during a robbery in Bucktown.

The police used a StingRay — the brand name for a secret cellphone tracker — to locate the victim’s stolen phone at a North Side apartment.

The apartment belonged to the girlfriend of Heriberto Viramontes, who was later arrested in the beating of Natasha McShane. Viramontes is serving a 25-year prison term for attempted murder. McShane recovered, but was severely disabled.

The Viramontes case is one at least 30 criminal investigations in which the Chicago Police Department used a StingRay tracker since 2010, according to documents the city was forced to make public because of an open-records lawsuit.

In 2014, Freddy Martinez, a Chicago privacy activist who works in the software industry, sued the city to release the documents. The city recently settled the case and turned over hundreds of pages of documents to Martinez and his attorney, Matthew Topic, of the law firm Loevy & Loevy.

Martinez wanted to know whether the city was using StingRays to spy on protesters and wanted to see whether police were fully disclosing how the devices work when officers went to judges asking to use them in investigations.

The documents don’t show any instances of police using StingRays to track demonstrators.

Instead, they show the devices were used in more than a dozen murder investigations; several kidnappings; and in drug-conspiracy cases involving gang members. In one of the kidnappings, the victim was located along with a suspect, according to the documents.

In another case, police were trying to recover a cellphone stolen from a police officer in a carjacking.

Martinez, though, doesn’t believe the city turned over everything.

“It is a suspiciously low number for a city the size of Chicago,” he said of the cases in which StingRays were used. “I still am not sure of the full extent of their use.”

The documents also show how the police described the devices to judges.

In one court application, an officer said he sought to use a “digital analyzer” that detects radio signals emitted automatically at the time a cellphone is turned on, and then periodically after that. The officer said the device “does not intercept any content of communications.”

Martinez said such descriptions didn’t fully explain the capabilities of the devices. They can track the location of numerous cellphones within a wide radius.

Civil rights activists have objected to such indiscriminate collection of personal cellphone data.

“I definitely do think they were not fully informing the courts on their use,” Martinez said.

The police department has been using StingRays for more than a decade, records show. The city has spent hundreds of thousands of dollars on the devices, which are manufactured by Harris Corp. in Florida. The Chicago police have used asset-forfeiture money to pay for them. The devices have been shrouded in secrecy partly because of nondisclosure agreements that local police agencies and federal agencies have signed with Harris Corp.

Earlier this year, Gov. Bruce Rauner responded to concerns over the use of StingRays by signing a law requiring the police to obtain court approval before using such cellular tracking systems. Police are required to delete any information they obtain from “non-target” phones. The law goes into effect on Jan. 1.