DoJ: Stingray cellphone tracking device falls under Fourth Amendment, but don't ask about it

In 2008, federal authorities arrested David Daniel Rigmaiden on charges of spearheading a massive identity theft ring in Arizona. Rigmaiden allegedly led this operation from January 2005 to April 2008, harvesting some $4 million off of more than 1,900 fraudulent tax returns. He was ultimately nabbed, however, thanks in part to controversial, and somewhat mysterious tool known as a "stingray" -- a device that effectively acts as a fake cell tower, allowing authorities to locate and track a cellphone even when it's not being used to place a call. Since his arrest, the 30-year-old Rigmaiden has been battling the feds in the U.S. District Court of Arizona, on allegations that their tracking tactics constituted an unlawful search and seizure, thereby violating his Fourth Amendment rights. For more than a year, the Department of Justice has maintained that the use of stingrays does not violate the Fourth Amendment. When it comes to sending data from a mobile device, the DoJ has argued, users should not have a "reasonable expectation" of privacy. Recently, though, the judge overseeing the case has indicated that he will press the feds for more information on how stingrays actually work -- something the government clearly has no desire to disclose. Prosecutors are so reluctant, in fact, that they may be willing to sacrifice their case against Rigmaiden in order to safeguard the stingray's secrecy. Read more about the latest developments, after the break.

Last week, the DoJ filed a memorandum in which it conceded that its tracking methods did indeed constitute "a Fourth Amendment search and seizure," ostensibly marking a 180-degree shift from its previous stance. But the government isn't willing to issue a full mea culpa. According to prosecutors, use of the stingray was authorized under a court order that investigators used to procure real-time tracking information from Verizon Wireless, Rigmaiden's service provider. Because of this, the Department argues, investigators did not have to obtain a second warrant to justify setting up a dummy cell tower. The defense, meanwhile, has countered with an argument that the aforementioned court order wasn't a valid warrant, because it allowed the feds to delete all collected data, in lieu of submitting them to the court. An FBI representative had previously told the Wall Street Journal that this policy "is intended to protect law enforcement capabilities so that subjects of law enforcement investigations do not learn how to evade or defeat lawfully authorized investigative activity." The prosecution elaborated upon that sentiment in its most recent memo, claiming that collected tracking information is deleted in order to guarantee "that the privacy rights of those innocent third parties are maintained."

So why would the government suddenly change its position on the stingray? According to court documents, it's willing to make these concessions in order to "avoid unnecessary disclosure" of further details on how the device works. In admitting that the use of stingrays constitutes a search and seizure as defined by the Fourth Amendment, the government is apparently looking to sidestep thornier litigation that could jeopardize the secrecy of its tactics. The DoJ was careful to note, however, that its most recent admission does not alter its fundamental philosophy that Rigmaiden did not "have a reasonable expectation of privacy in his general location or in the cell site records he transmitted wirelessly to Verizon." The defense did not respond to the Journal's request for comment, though it did state its intent to file a response this week.