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.