A federal judge in Iowa has ruled that evidence gathered through the warrantless use of covert GPS vehicle trackers can be used to prosecute a suspected drug trafficker, despite a Supreme Court decision this year that found such tracking unconstitutional without a warrant.

U.S. District Judge Mark Bennett in Sioux City ruled last week (.pdf) that the GPS tracking evidence gathered by federal DEA agents last year against suspected drug trafficker Angel Amaya, prior to the Supreme Court ruling, can be submitted in court because the agents were acting in good faith at the time. The agents, the judge said, were relying on what was then a binding 8th U.S. Circuit Court of Appeals precedent that authorized the use of warrantless GPS trackers for surveillance in Iowa and six other states.

It's the third of such "good faith" rulings by federal court judges in the wake of the recent and historic Supreme Court decision, all of which illustrate that the Supreme Court ruling can be easily skirted by law enforcement agents and prosecutors who work in circuit court regions where it was previously legal to use the devices without a warrant.

Legal experts say the "good faith" exception, which comes out of another court ruling last year, has created a mess of the Supreme Court's GPS decision.

"[I]t is a bit of an end-run around for law enforcement," says Hanni Fakhoury, staff attorney for the Electronic Frontier Foundation. "And it leads to disparate results because whether [GPS evidence] gets suppressed or not depends on what the law of the circuit was prior to Jones."

Circuit courts in the 7th (covering Illinois, Wisconsin and Indiana), 8th (covering Arkansas, Iowa, Minnesota, Missouri, Nebraska, North Dakota and South Dakota) and 9th (covering Alaska, Arizona, California, Guam, Hawaii, Idaho, the Mariana Islands, Montana, Nevada, Oregon and Washington) all ruled prior to the Supreme Court case that warrantless GPS tracking was legal.

If followed by other courts in these circuits, this means that law enforcement agents and prosecutors in 19 states, as well as Guam and the Mariana Islands, can use the so-called "good faith exception" to support warrantless GPS surveillance in pending cases where data was gathered prior to the Supreme Court ruling, while those in other states cannot.

"If we're going to apply the law one way in half the country and another way in the other half of the country, that’s a real problem," Fakhoury says.

Amaya's defense attorney expressed surprise at the decision in that case.

"I'm not sure where this is coming from to be honest with you," said R. Scott Rhinehart in a phone call, noting that the Supreme Court case did not raise the issue of a "good faith" exception to the use of GPS tracking.

The case involves GPS devices that were used by DEA agents to repeatedly monitor the movements of Amaya over several months, beginning in March last year.

Amaya was indicted last July on charges that he possessed, and conspired with others to distribute, large amounts of methamphetamine, cocaine and marijuana. During their investigation, DEA agents secretly placed GPS trackers on nine vehicles belonging to various suspects, including three driven by Amaya.

A court document provides interesting insight into how the devices were used.

On Mar. 18, 2011, acting on a tip from state troopers, DEA agents attached a GPS device to Amaya’s GMC Yukon while it was sitting in the driveway of his residence. Once it was in place, agents either changed the batteries on the device or switched out the old device with a new one on four occasions, according to court documents: three times while it was sitting in Amaya's driveway, and once while it was in a Best Buy parking lot.

A GPS tracker was also placed on another vehicle Amaya was driving after agents learned from a court-authorized wiretap that he was planning a secret trip to Texas. This time, it appears that agents arranged for police to pull over the blue Nissan Murano, and then covertly attached the device.

Another GPS device was used to track a Nissan Maxima after agents received information from wiretaps that a large amount of cash was going to be concealed in the vehicle, which would then be transported on a car trailer from Iowa to California.

On Apr. 30, 2011, Amaya took the car to a former Wal-Mart parking lot, where it was loaded onto a tractor trailer car carrier. Agents subsequently contacted the truck driver and had him divert the trailer to a location in Nebraska, where they searched the vehicle and found about $29,000 in cash. Agents then changed the battery on the GPS device and sent the tractor trailer and Maxima on their way to California, where the GPS device was later retrieved from the vehicle in August.

Throughout their use of the trackers, agents switched the GPS devices on and off remotely to conserve battery life when they weren't needed, such as when an agent was trailing Amaya in another car. When switched on, the GPS devices were set to ping at 15-second intervals, and the location of the vehicle would be displayed on a website available to the agents.

Law enforcement's use of GPS vehicle trackers came under increased scrutiny last year when the U.S. Supreme Court took up the case of United States v. Jones, which also involved the use of GPS trackers in a drug investigation.

Antoine Jones was given a life sentence by a lower court for drug trafficking, based in part on evidence gathered with a GPS vehicle tacker placed on his Jeep. A federal appeals court in Washington, D.C., later ruled that collecting data from the GPS device amounted to a search, and therefore required a warrant. Prosecutors argued that the device only collected the same information that anyone on a public street could glean from physically following the suspect. But the appellate court judge wrote in his ruling that the persistent, nonstop surveillance afforded by a GPS tracker was much different from physically tracking a suspect on a single trip.

The Obama administration called the appellate decision “vague and unworkable,” and petitioned the Supreme Court to rule that authorities did not need to obtain a warrant to use the devices. The Supreme Court justices ruled earlier this year in January that GPS tracking of a suspect's vehicle qualified as a search under the U.S. Constitution, but stopped short of ruling that authorities needed to obtain a warrant every time they used a tracker.

The justices said that law enforcement authorities might need a probable-cause warrant from a judge, but did not say definitively whether such a search was unreasonable and required a warrant. Most legal experts, however, say the implication is that the use of such devices would require a warrant.

The ruling reportedly prompted the Federal Bureau of Investigation to disable some 3,000 trackers that were in use in the field at the time the ruling came out, and to begin drafting new guidelines for using the devices.

The Jones case left open the question of whether a warrant is required for GPS monitoring or if, instead, warrantless GPS monitoring is lawful when officers have reasonable suspicion or probable cause to believe that a vehicle is involved in illegal activity.

In the Amaya case, Judge Bennett sidestepped that issue entirely and did not even consider whether the DEA agents had reasonable suspicion or probable cause to use the devices to track Amaya. Instead he made his ruling based solely on the "good faith" exception from a 2011 Supreme Court case, Davis v. United States (.pdf).

The Davis ruling allows a good-faith exception for searches that reasonably relied on binding precedents that were later found to be faulty.

Judges in two other GPS cases in California and Hawaii, both in the 9th Circuit where a precedent ruling exists, asserted the same "good faith" exception last month. Fakhoury says the problem isn't with the way judges are applying the Davis ruling, but in the Davis ruling itself.

"Davis is a really poorly-reasoned, not well-thought-out opinion," he says. He expects the same thing will happen in other kinds of cases where various Circuit courts around the country have split on a ruling, and the Supreme Court makes a final ruling that ultimately won't apply in states where a precedent ruling existed.

"This situation is just going to keep popping up again and again," he says. "And the whole point of a Supreme Court ruling is to clarify the law and make it uniform across the country."