The New York Police Department won’t have to reveal details about its portable cellphone tracking system commonly known as Stingrays.

The New York Civil Liberties Union had sued the NYPD in 2016 for specific information on its Stingray program after a records request under the state’s Freedom of Information Law was denied.

On Wednesday, a judge ruled the information should remain confidential, saying that disclosing it would help wrongdoers evade detection.

An NYCLU attorney said it may appeal.

The suitcase-sized devices can sweep up cellphone data from an entire neighborhood. Some can even intercept texts and calls.

About a dozen states now have laws requiring warrants to use the technology. A judge in New York City last year ruled the NYPD must have an eavesdropping warrant to use the device.