Electronic surveillance

Federal agents will no longer use 'Stingray' cellphone trackers without warrants

Immigration, Secret Service, and Homeland Security investigators must now obtain search warrants before using "Stingray" trackers that reveal the locations of scores of cellphone users, aDepartment of Homeland Security official told a House panel Wednesday.

The new policy comes in response to growing criticism from members of Congress and civil liberties groups that law enforcement agencies have been violating Americans' constitutional rights against unreasonable searches and seizures by secretly using Stingray technology without warrants.