Fake mobile phone towers, often called Stingrays, offer valuable information about suspects but also collect vast amounts of data from innocent passers-by. From now on, agencies will need to obtain a search warrant to use such devices. The US Department of Justice said it wanted to protect citizens' privacy. "Cell-site simulator technology has been instrumental in aiding law enforcement in a broad array of investigations, including kidnappings, fugitive investigations and complicated narcotic cases," Deputy Attorney General Sally Quillian Yates said in a statement. "This new policy ensures our protocols for this technology are consistent, well-managed and respectful of individuals' privacy and civil liberties," she added. The policy, which takes effect immediately, applies to the Federal Bureau of Investigation (FBI) the Bureau of Alcohol, Tobacco and Firearms, the Drug Enforcement Administration (DEA) and the United States Marshals Service. I...