The Electronic Frontier Foundation filed a lawsuit Monday in order to learn more about the United States Marshals Service’s use of airborne cell-site simulators

The San Francisco-based advocacy group filed a Freedom of Information Act (FOIA) request with the Department of Justice (DOJ), the USMS’ parent agency, shortly after the revelations came to light in November 2014. However, the DOJ has not produced any responsive documents and has long exceeded the 30-day deadline as defined under the FOIA law.

In the suit, which was filed in federal court in Washington, DC, the EFF asks the court to compel the DOJ to immediately produce the documents. The DOJ did not immediately respond to Ars’ request for comment.

Last fall, The Wall Street Journal reported that the US Marshals Service (USMS) was using small, fixed-wing Cessnas equipped with so-called DRTboxes—“dirtboxes.” The devices are receivers that spoof a cell tower to gather data from citizens' phones below. The purpose of such collection is to target and spy on criminal suspects, but the data from any nearby citizen's phone is also collected by such devices.

The dirtbox gets its name from the Boeing division that makes them—Digital Receiver Technology or DRT. On its website, Boeing says that DRT creates “a miniature yet powerful receiver measurement capability to test and monitor wireless signals... While other products require multiple scanners linked together to perform similar system measurements, Boeing offers this capability within a single portable product.”

No way, no how

The devices are believed to have stronger capabilities comparable to the “StingRay,” a trademarked product sold by the Harris Corporation, which has been very tight-lipped about its specifications. Stingray, though, has come to be used as a generic name for this entire class of devices, which are also known as cell-site simulators and IMSI catchers. While stingrays have long been known to be used by federal, state, and local law enforcement, this marks the first time that such an agency has been reported to have deployed the equipment onto airplanes.

In a newly disclosed document, Ars also reported Tuesday that the FBI has been notified every time a local law enforcement agency receives a public records request under state law.

Christopher Allen, an FBI spokesman, declined to answer Ars’ previous questions on this policy, but on Tuesday provided a statement that the agency has previously used in other related legal cases.

The statement reads: