NEW YORK — New York City, Los Angeles, Chicago and Las Vegas are among scores of police departments across the country quietly using a highly secretive technology developed for the military that can track the whereabouts of suspects by using the signals constantly emitted by their cellphones.Civil liberties and privacy groups are increasingly raising objections to the suitcase-sized devices known as StingRays or cell site simulators that can sweep up cellphone data from an entire neighborhood by mimicking cell towers. Police can determine the location of a phone without the user even making a call or sending a text message. Some versions of the technology can even intercept texts and calls, or pull information stored on the phones.Part of the problem, privacy experts say, is the devices can also collect data from anyone within a small radius of the person being tracked.