Maryland U.S. Attorney Rod J. Rosenstein told the 4th Circuit court that investigators do not need warrants to obtain cellphone location records from wireless providers to track criminal suspects. (Michel du Cille/The Washington Post)

A federal appeals court on Wednesday considered how easily investigators should be able to track criminal suspects through their cellphones, becoming the latest front in the debate over how to balance public-safety interests with digital privacy.

The issue before a full panel of the U.S. Court of Appeals for the 4th Circuit, which has jurisdiction over Maryland and Virginia, was whether law enforcement officials need search warrants to pull cellphone records to trace the long-term movements of suspects.

The case, argued in Richmond, arose after investigators in Maryland obtained seven months of phone records to map the movements of two men later convicted in armed robberies around Baltimore.

Almost immediately Wednesday, questions from the bench centered on whether location information from cellphones is any different than records of banking transactions or landline phone calls.

Defense attorney Meghan S. Skelton said the government had essentially tracked the defendants’ every move, equating cellphone location data to “dragnet surveillance.” Maryland U.S. Attorney Rod J. Rosenstein countered that the information gleaned from cell towers was imprecise, unobtrusive and created by the wireless provider — not the government.

A divided three-judge panel of the court ruled in August that accessing the location information without a warrant for an “extended period” is unconstitutional because it allows law enforcement to trace a person’s daily travels and activities across public and private spaces.

Two other federal appellate courts — in Florida and New Orleans — concluded that warrants are not necessary.

The full spectrum of opinions was on display Wednesday from the 15 judges in the spirited hour-long discussion.

Judge James A. Wynn Jr. expressed disbelief about the length of time — 221 days — that investigators had collected records for suspect, Aaron Graham, to help place him near the scene of the robberies after his arrest.

“We all know where technology is going,” Wynn said. “They are going to be able to pinpoint your every move.”

Texting, calling, and checking email or the weather from a cellphone generally involves connecting with the closest communications tower. Wireless providers log and retain records showing which tower a phone used at the beginning and end of every call, and increasingly, for texts and data connections.

Decades-old rules allow authorities to obtain business or “third party” records with a court order.

Judge Paul V. Niemeyer pointed out that authorities already could obtain — without a warrant — even more precise details about a person’s travels by pulling records from credit card purchases and highway E-ZPass transponders.

Judge J. Harvie Wilkinson III said the “third party” rules do not need to change because of technological advances, and that to do so would be “an audacious step” away from the court’s past practice.

Civil liberties groups and privacy advocates want investigators to have to get a warrant first for the tracking, because a warrant request requires that judge be presented with information to support the request that would meet the more rigorous gold standard of probable cause.

Judge Pamela A. Harris, the newest member of the court, noted that the Supreme Court has signaled that digital devices are different when it comes to 4th Amendment protections against unreasonable search and seizure.

Justices have expressed concern about privacy implications of technology such as cellphones that contain sensitive personal information, and are essentially appendages in people’s purses, pockets and hands.

If the full 4th Circuit upholds its panel’s decision, there would be a clear divide with the other courts — the type of split that often attracts the attention of the Supreme Court.