Patch from the Baltimore Police Department uniform.r (Patrick Semansky/AP)

Several civil liberties organizations filed a complaint Tuesday asking the Federal Communications Commission to investigate the use of cellphone tracking devices by the Baltimore Police Department.

The complaint alleges that the Baltimore police, like many other police agencies across the country, are using devices that mimic cellphone towers to track suspects through their cellphone locations, in violation of federal law that requires a license.

The groups are also alleging that the use of the disruptive surveillance technology overwhelmingly affects black residents — and does so without appropriate transparency and oversight.

“There’s a pattern of law enforcement agencies around the country engaging in racially discriminatory policing, and that extends to surveillance technology,” said Laura Moy, director of Georgetown University’s Institute for Public Representation, who filed the complaint on behalf of the groups.

The Communications Act, the groups say, requires a license to operate the devices on frequencies reserved for wireless carriers.

But an FCC official said Monday that local police agencies do not need a license under the law. The official, who spoke on the condition of anonymity because she was not authorized to talk on the record, said at one point that the devices do not transmit on the wireless spectrum — which experts dispute. At another point, she suggested that local law enforcement is exempt from the requirement. In general, she could not give a clear explanation of why a license is not needed.

Moy said, “I think it’s a pretty clear violation, and I think the FCC has been looking the other way for a long time, hoping nobody will notice.”

The use of the cell site simulators, which are sometimes called Stingrays after one of the most popular models, has stirred controversy because of the great secrecy surrounding their use. Last September, the Justice Department announced a new policy that requires federal law enforcement agencies to obtain a warrant to use the devices and to inform judges when they plan to deploy them. But the policy does not apply to state and local agencies.

The devices are boxes about the size of a small suitcase that can help police locate suspects by identifying signals coming from their phones. But the machines also sweep up data from innocent bystanders in the suspect’s vicinity, raising privacy concerns. The data captured by the devices are serial numbers from cellphones, not GPS coordinates.

The Baltimore Police Department is also violating the law by “willfully interfering” with the commercial cellular network through its use of the equipment, alleged the Center for Media Justice, Color of Change, and New America’s Open Technology Institute.

The devices send out signals that force nearby cellphones to connect to them, disrupting regular cellphone service as people who were on or making a call lose their connection to the real tower. Such disruptions could also interfere with emergency services, the groups said in their complaint, a copy of which was shared with The Washington Post.

The FCC official said the commission is reviewing that issue. In 2014, it warned the public “it is illegal to use a cell phone jammer or any other type of device that blocks, jams or interferes with authorized communications.” The prohibition, the FCC said, “extends to every entity that does not hold a federal authorization, including state and local law enforcement agencies.”

“We look forward to reviewing the complaint filed today,” said FCC spokesman Neil Grace. “The commission expects state and local law enforcement to work through the appropriate legal processes to use these devices.”

The Baltimore Police Department declined to comment.

The harms that result from police use of the equipment “fall disproportionately” on Baltimore’s black residents, the advocacy groups said.

The complaint comes on the heels of a scathing Justice Department investigation that found that the police department routinely violated the civil rights of the city’s black residents. The police engaged in a “pattern or practice” of making unconstitutional stops, using excessive force and retaliating against residents exercising their right of free speech, the Justice Department said.

“The Baltimore Police Department uses cellphone interceptors at an astronomically higher rate than other law enforcement agencies, and mostly does so in black neighborhoods,” said Steven Renderos, senior campaign manager at the Center for Media Justice. In light of the Justice Department report, he said, “the Federal Communications Commission cannot allow a device as powerful as a cellphone interceptor to operate in obscurity. Unlicensed use of this technology decreases police accountability and increases the potential for harm against African Americans.”

In March, the Maryland Court of Special Appeals held that the Baltimore police must obtain a probable-cause warrant to use a cell site simulator and disclose the intended use to a judge. That ruling came in a case involving a man wanted on charges of attempted murder.