Police in Anaheim, California have been using Stingray surveillance devices, as well as their more intrusive cousin, "dirtboxes," during active investigations, completely unbeknownst to residents. New documents — more than 400 of them — obtained by the American Civil Liberties Union indicate that the department has requested funds for the technology, and that it's been using those devices since at least 2009.

Dirtboxes have been used during aerial missions to capture data on thousands of phones at once. Some versions can decrypt communications, allowing law enforcement to eavesdrop on conversations, emails, and text messages. It isn’t clear what kind of surveillance the dirtbox possessed by the Anaheim police department is capable of conducting or if it's been used in the air, but one email obtained by the ACLU does say it was used during narcotics investigations.

In addition to its dirtbox, the police force purchased multiple Stingray devices, including one that can monitor LTE networks. It also bought a hand-held surveillance device that assists in locating phone and LTE signals when phones are in more secure locales, like inside a building.

The surveillance technology purchased by the Anaheim police hasn’t only impacted local residents. The documents show that the force lent its tech to police departments all over Orange County. Three million people live in Orange County, and 16 million people visit Disneyland every year, all of whom could potentially have been surveilled by the devices. The ACLU notes that the documents say "court orders" and "court approvals" were obtained before deploying them, but that doesn’t necessarily mean a warrant under probable cause was issued.

The veil shrouding these devices has slowly been lifting ever since the Electronic Frontier Foundation and ACLU exposed the technology during a 2012 case. In response to increased scrutiny, the Department of Justice and the Department of Homeland Security pledged to seek warrants before deploying them. Individual states, including California, also passed legislation requiring warrants. Still, the devices continue to be used without the knowledge of citizens and often pick up on innocent bystanders’ cell phone data.