03/19/2013 07:02 pm ET Updated May 19, 2013

Judge In Stingray Cell Tower Spoofing Case Puts Government On Notice

The judge in a criminal case that could reveal information about a mysterious cellphone tracking technology put the government on notice last week, telling them they better be prepared to discuss in detail sensitive questions during a March 28 hearing.

At issue is how forthcoming the government was when it got a federal magistrate judge to issue court orders for the use of a device called a stingray to find the man allegedly behind a large-scale tax fraud scheme, Daniel David Rigmaiden. Civil liberties advocates have argued that the government concealed the true capabilities of stingrays, which trick cellphones into thinking they are communicating with legitimate cell towers when they are actually revealing their location to law enforcement.

The Justice Department has strenuously sought to avoid making details about stingrays public, and in court filings, it has claimed that its tracking warrant was nothing out of the ordinary. But in a March 14 order, US District Judge David G. Campbell told the feds they "should provide support for that assertion."

"Both Defendant and the ACLU argue that the warrant application for the mobile tracking device was inadequate because it did not include the technical details about how the device worked," Campbell wrote. "The government could address this argument in greater detail and identify any specific authority to support its position."

The government has also argued that if any of its investigatory methods ran afoul of the Constitution, they should still get to use evidence produced by those methods because they were acting in good faith. The judge asked Rigmaiden to tell the court what he thought of that.