The American Civil Liberties Union of California has learned that Anaheim police maintain an inventory of cell phone surveillance devices including surveillance devices designed for Cessna planes.

The Anaheim police possess three different forms of cell phone surveillance tools, according to the newly released documents. These devices are known as cell site simulators or sometimes Stingrays. In 2011, Anaheim police purchased a Stingray and in 2013, Anaheim’s Chief of Police approved an upgrade.

Truth In Media has written extensively about how these devices are being used to track suspected criminals while largely operating without oversight from local, state, or federal authorities. Exactly how the devices operate and what data they collect and/or save has been unknown because of a vast amount of secrecy surrounding the tools.

The Electronic Frontier Foundation describes the Stingray as “a brand name of an IMSI (International Mobile Subscriber Identity) Catcher targeted and sold to law enforcement. A Stingray works by masquerading as a cellphone tower– to which your mobile phone sends signals to every 7 to 15 seconds whether you are on a call or not – and tricks your phone into connecting to it.”

[READ MORE: A Guide to Stingray Cellphone Surveillance Technology]

Much of the information has been released through Freedom of Information Act (FOIA) requests related specifically to the manufacturer of the Stingray – the Harris Corporation. The Harris Corporation has exercised a great amount of secrecy surrounding these tools. Truth In Media previously reported on documents which revealed the Harris Corp. worked with the Federal Communications Commission to maintain a high level of secrecy. Truth In Media has also discussed the fact that Harris Corp. lied to the FCC in their application for the use of cell site simulators.

The documents obtained by the ACLU also reveal that Anaheim police possess another powerful cell site simulator known as a “dirtbox.” The dirtbox is a military-grade surveillance tool made by Digital Receiver Technology Inc., or DRT. In 2009, Anaheim police used a federal grant to purchase a dirtbox. The device is capable of collecting information from thousands of phones at once.

The Center for Investigative Reporting wrote:

“The sophisticated surveillance equipment, manufactured by Digital Receiver Technology (DRT) Inc., a Maryland company acquired by The Boeing Co. in 2008, provides a more powerful class of cell-site simulator than the more widely used StingRay devices produced by Harris Corp., which require an upgrade to intercept communications and data transmissions. According to Digital Receiver Technology’s documentation, its devices are capable of breaking encryption on communications from 200 cellphones simultaneously across state-of-the-art 4G LTE frequencies used for rapid data transmission by the latest generation of smartphones.”

The documents also highlight how Anaheim police loaned out their surveillance equipment to local police departments outside their jurisdiction. In funding requests, the police wrote that “every city in Orange County has benefited” from their surveillance tools. The Anaheim police make it clear that the surveillance tools are available to other police departments in Orange County and also maintain written procedures for sharing the dirtbox.

[RELATED: Chicago, L.A. Police Using ‘Stingray’ Surveillance Capable of Breaking Encryption]

The ACLU says the spying program could potentially affect the privacy of Orange County’s 3 million residents and possibly the 16 million people who visit nearby Disneyland every year.

There is also concern over Anaheim police using the surveillance device in planes. An email from Lt. Dave Vangsness, head of the Anaheim Police Department’s Air Support Bureau, contains a memorandum of understanding for the dirtbox.

This would not be the first time that government agencies used planes outfitted with surveillance equipment to monitor the public. In late 2014, the Wall Street Journal revealed the existence of a cell-phone monitoring program being operated by the U.S. Marshals Service using Cessna planes mounted with dirtboxes.

The Electronic Frontier Foundation filed a FOIA request with the Department of Justice and FBI but has yet to receive any additional information. The EFF has now filed suit against the DOJ and FBI.

In early March of 2015, it was revealed that the CIA has been working with the Marshals on the program. Over the last ten years, the U.S. Marshal’s Technical Operations Group worked with the CIA’s Office of Technical Collection to develop the technology. The agencies have spent more than $1 million developing the technology.

In June 2015, it was also revealed that agencies within the U.S. government operate fake, front companies to handle surveillance flights. Some of these flights included monitoring protesters in Baltimore.

In late 2013, Anaheim police also purchased a hand-held cell phone surveillance device manufactured by a company called KEYW. The tool is designed to covertly locate phone and encrypted LTE signals. The ACLU compared the documents with publicly available price quotes and concluded that the Anaheim police bought a device called a Jugular.

“With a lightweight Jugular in hand, individual officers can easily conduct cell phone surveillance around and inside of buildings, including private homes, without alerting bystanders,” the ACLU wrote.