Cellphone users have a reasonable expectation of privacy as to their location and police in New Jersey have to obtain a warrant to track a criminal suspect's phone, the New Jersey Supreme Court ruled on Thursday.

"Using a cellphone to determine the location of its user can be far more revealing that acquiring toll billing, bank, or Internet subscriber records," wrote Chief Justice Stuart Rabner for the court in State v. Earls, A-53-11.

"It is akin to using a tracking device and can function as a substitute for 24/7 surveillance without police having to confront the limits of their resources. It also involves a degree of intrusion that a reasonable person would not anticipate."

The ruling, based solely on state constitutional law, parts company with the U.S. Supreme Court, which has ruled cell users have no reasonable expectation of privacy in public locations.

Because the decision creates a new rule, it will apply only to the defendant and to prospective cases. The court gave the Attorney General's Office 30 days to issue guidelines to state, county and local law enforcement agencies.

Thomas Earls was a suspect in a series of break-ins in Middletown in 2006. Without a warrant, police asked his service provider, T-Mobile, for information about his phone's location. Cellphones send out signals every few seconds to determine the location of the nearest cell tower, and that traffic is recorded by the service provider.

Based on the cell data obtained, police got an arrest warrant and found Earls at a motel in Howell. Information provided by his girlfriend led to finding stolen goods in a nearby storage locker.

Charged with multiple burglary counts, Earls took a plea bargain he is now attempting to withdraw. He argues that obtaining information from T-Mobile without a warrant violated his privacy rights under the U.S. Constitution's Fourth Amendment and the New Jersey Constitution, art. 1, ¶ 7.

Rabner noted that cellphones and other mobile devices provide "an intimate picture of one's daily life," including which "shops, doctors, religious services, and political events" one uses and attends. "This is not a voluntary disclosure in a typical sense; it can only be avoided at the price of not using a cellphone," he said.

As of 2012, there were 326.4 million wireless devices in the United States, said Rabner, adding that according to the Pew Research Center, 91 percent of adults own a wireless device and 56 percent have a smart phone.

"New improvements not only expand our ability to communicate with one another and access the Internet, but the cellphones we carry can also serve as powerful tracking devices able to pinpoint our movements with remarkable precision and accuracy," Rabner said, noting a service provider can track a cellphone's location to a particular room in an office building.

"Although individuals may be generally aware that their phones can be tracked, most people do not realize the extent of modern tracking capabilities and reasonably do not expect law enforcement to convert their phones into precise, possibly continuous tracking tools," he said.

The U.S. Supreme Court ruled last year, in U.S. v. Jones, 132 S. Ct. 945 (2012), that law enforcement officers violated a defendant's Fourth Amendment rights when they attached a GPS device to his car. However, the court found that the installation of the GPS amounted to a trespass on private property. The majority decision did not address whether there was a privacy violation when they monitored the device's location.

Rabner said that the New Jersey Supreme Court, as it has done often in the past, used the state Constitution as a platform to guarantee more rights to individuals than the federal courts using the U.S. Constitution.

Law enforcement, he said, can still track a suspect's cellphone location after obtaining a warrant, or if there are exigent circumstances.

Rabner said the state already requires, under N.J.S.A. 156A-29e, that police get warrants for cellphone location information when they have less than probable cause. He also alluded to statements made during oral arguments by Deputy Attorney General Brian Uzdavinis that, in recent years, the state has required that police first obtain a warrant before seeking cellphone location information.

"We credit the Attorney General's office for that approach," he said.

Earls' designated counsel, Columbus solo Alison Perrone, says Earls already has served his sentence and is unsure whether he will move at this point to vacate his plea. The court did not vacate the plea and remanded the case to the Appellate Division to determine if it should be vacated on other grounds.

"The court is taking a strong stand in stating unequivocally that people have a reasonable expectation of privacy, and it is protecting them with the warrant requirement," she says. "This has the potential to affect many people since the court is telling the police that they cannot use cellphones as a tracking device."

The American Civil Liberties Union of New Jersey and the Association of Criminal Defense Lawyers of New Jersey participated as amici. They were represented by Rubin Sinins.

"Cellphones are not meant to be used as tracking devices by law enforcement," says Sinins, of Springfield's Javerbaum Wurgaft Hicks Kahn Wickstrom & Sinins. "No one buys a cellphone so the police can track them."

The Washington, D.C.-based Electronic Privacy Information Center also participated as amicus. Staff counsel Alan Butler echoed Sinins' sentiments.

"The court made it abundantly clear that merely owning and using a cellphone does not mean you can be tracked without consent," Butler says.

Uzdavinis, during oral argument, had argued that if the court were to adopt the warrant requirement, it should be applied prospectively because the police, at the time of the investigation into Earls break-in, were following the rules that were in place at the time.

Earls had no reasonable expectation of privacy at that time, Uzdavinis argued, because technology at that time could only locate his phone within a mile of the closest cell tower.

Peter Aseltine, a spokesman for acting Attorney General John Hoffman, says police already are routinely seeking search warrants based on probable cause before asking providers for cellphone location information. "We will implement training for New Jersey law enforcement to ensure compliance with this ruling," he says. •