(WSJ) The U.S. Department of Justice now says its use of a cellphone-tracking device in a controversial Arizona case could be considered a “search” under the Fourth Amendment, a tactical move legal experts say is designed to protect the secrecy of the gadgets known as “stingrays.”

For more than a year, federal prosecutors have argued in U.S. District Court that the use of the stingray device—which can locate a mobile phone even when it’s not being used to make a call—wasn’t a search, in part because the user had no reasonable expectation of privacy while using Verizon Wireless cellphone service. Under that argument, authorities wouldn’t need to obtain a search warrant before using one of the devices.

The defendant in the case, Daniel David Rigmaiden, is facing fraud charges. His quest to force the government to provide information about the device used to locate him was the subject of front-page article in The Wall Street Journal in September. Legal experts say the government’s move fits into its strategy of keeping information about the devices under wraps, and the government continues to maintain that, in general, search warrants aren’t required. Full Story