Techies have known for years that perhaps the FBI’s most sophisticated surveillance tool, known as the Stingray, mimics a cellphone tower and can pinpoint the location of hundreds of people at a time.

The G-Men were able to keep a secret, but then they gave dozens of the suitcase-sized devices to city police departments across the country. Instructions were to admit nothing and preserve secrecy at all costs, even if it meant dropping a case.

Of course, the local LEOs have blown it, using terrorist-hunting technology to find people suspected of the most petty of crimes, as well as anybody else who might be in the vicinity. In the process they got the Stingray splashed across the front page of USA Today. That probably isn’t going over well at the J. Edgar Hoover Building.

In Maryland, where the newspaper did the bulk of its research, records revealed that state law was often broken, because defense attorneys must be told about electronic surveillance. Judges were snowballed or outright deceived. Sometimes, so were prosecutors.

Matters such as whether search warrants are required or the Stingray itself is constitutional must be hashed out state by state. Expect a flurry of ACLU lawsuits.

In terms of national security and hunting the truly dangerous, damage has been done, but the fallout goes all the way to the streets. Those who want to elude capture will change tactics. Defense attorneys now know if they press the subject of the Stingray that charges might be reduced or dropped.

All because a few police departments misused the feds’ toy.

From the libertarian view, a possible silver lining: We might find that the same judges who allowed the Fourth Amendment to be brutally hacked to death don’t cotton to being bamboozled.