Police must get a warrant before using GPS to track a suspect’s vehicle, a federal appeals court has ruled, throwing out a cache of evidence against three brothers charged in a wave of pharmacy burglaries and going beyond a Supreme Court ruling that left open the question of whether judges have to approve of the high-tech surveillance.

State police investigating the pharmacy burglaries were making progress in 2010 when they found tools, gloves and a ski mask in a search of suspect Harry Katzin’s van.

The electrician said they were merely tools of his trade, and police let him go. But police, working with the FBI, soon put a GPS device under his bumper and closed in on the van after another burglary. They found Katzin and his two brothers inside, along with a large stash of pills, cash and other store property.

Three years later, the evidence has been tossed out after the 3rd U.S. Circuit Court called the GPS tracking an illegal search. The Katzins, who have pleaded not guilty, are free on bail.

The Supreme Court ruled in January 2012 that GPS tracking amounts to a police search, but left open the question of whether such searches require warrants. The 3rd U.S. Circuit Court said they do, unless there’s an imminent danger.

Judge Joseph A. Greenaway wrote in a 2-1 opinion for the court last month that a GPS tracker is different than human surveillance because “it creates a continuous police presence” meant to discover future evidence.

“This case in our view is very significant,” said lawyer Catherine Crump, who argued on behalf of the American Civil Liberties Union. “Where people go can reveal a great deal about them, from who their friends are, to what their daily routine is …to what doctors they visit. All of that information, especially when considered together, contains a detailed portrait of someone’s life.”

The Justice Department is weighing an appeal, according to Assistant U.S. Attorney Robert Zauzmer. He had argued that police acted in good faith before the ruling from the Supreme Court. And one of the three judges agreed the evidence should not be suppressed for that reason.

The Katzins — Harry, Michael and Mark — allegedly sold prescription drugs from the house they lived in across from a public school. A police raid turned up $28,000 worth of OxyContin, Xanax, Ritalin, morphine and amphetamines at the house, Zauzmer wrote last year in opposing bail, when he called the evidence “overwhelming.”

One law enforcement expert agreed, but said that evidence found during the investigation before the GPS was attached should have been used as probable cause to get a warrant.

“The rule of thumb is, if you have time to get a warrant, get a warrant,” said Vernon Herron, a former Maryland State Police commander who now works as a senior policy analyst at the Center for Health and Homeland Security, part of the University of Maryland.

Police used GPS devices during his tenure, but they could only dream of the technology available today, when police can follow someone’s every move from a laptop, Herron said.

U.S. District Judge Gene Pratter first ordered the evidence in the Katzins’ case suppressed last year, writing that the GPS device recorded information “that investigators could have observed by conducting physical surveillance.”

But police surveillance is costly, and therefore subject to built-in limitations, Crump said. Cheap GPS devices, on the other hand, present no such barrier.

“When we started out, the Supreme Court hadn’t weighed in… and the majority of the law was actually contrary to our position,” said Mark Katzin’s lawyer, Rocco Cipparone, who argued the defense case. “My hope is that the government won’t (appeal).”

(AP)