WASHINGTON (CBSDC/AP) — A recent Supreme Court ruling that bars police from installing GPS technology to track suspects without first getting authorization for a judge is creating problems for the FBI.

The agency has been forced deactivate its GPS tracking devices in some investigations, FBI director Robert Mueller said Wednesday.

Mueller told a congressional panel that the bureau has turned off a substantial number of GPS units and is using surveillance by agents instead.

“Putting a physical surveillance team out with six, eight, 12 persons is tremendously time intensive,” Mueller told a House Appropriations subcommittee. The court ruling “will inhibit our ability to use this in a number of surveillances where it has been tremendously beneficial.”

The Supreme Court voted unanimously in favor of the measure in January.

“We have a number of people in the United States who we could not indict, there’s not probable cause to indict them or to arrest them who present a threat of terrorism, articulated maybe up on the Internet, may have purchased a gun, but taken no particular steps to take a terrorist act,” Mueller said. “And we are stuck in the position of surveilling that person for a substantial period of time.”

GPS trackers “enabled us to utilize resources elsewhere,” the FBI director added.

Mueller said the FBI will comply with the court decision and will make certain that whatever test is ultimately adopted, that the bureau will adhere to that in terms of using GPS.

In a Feb. 24 appearance at the University of San Francisco, FBI General Counsel Andrew Weissmann described just how significant the ruling is viewed in federal law enforcement. He said that in the Justice Department, it is seen as “a sea change” stemming from language in a concurring opinion in the case by Justice Samuel Alito.

Alito wrote that “the use of longer-term GPS monitoring in investigations of most offenses impinges on expectations of privacy.” Alito was joined by Justices Ruth Bader Ginsburg, Stephen Breyer and Elena Kagan. Justice Sonia Sotomayor said she agreed with Alito’s conclusion.

Alito is a former U.S. attorney and is viewed as part of the conservative wing of the Supreme Court.

The legal team for the nightclub owner criminal defendant in the case did an effective job of presenting “the specter of what I think they called drone law enforcement,” Weissman said at the university during a law school conference entitled “Big Brother In the 21st century.”

Weissman said that the idea the other side so effectively conveyed was that “there was no longer a human element that could put a check on what law enforcement would do.”

Catherine Crump, a lawyer for the American Civil Liberties Union, said “worries that proper judicial oversight like warrant requirements unduly hamper investigations are unfounded, as many law enforcement agencies routinely obtain such approval for GPS tracking.”

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