On a cloudless spring day, the NYPD helicopter soars over the city, its sights set on the Statue of Liberty. A dramatic close-up of Lady Liberty's frozen gaze fills one of three flat-screen computer monitors mounted on a console. Hundreds of sightseers below are oblivious to the fact that a helicopter is peering down on them from a mile and a half away. They don't even know we're here," said crew chief John Diaz, speaking into a headset over the din of the aircraft's engine. The helicopter's unmarked paint job belies what's inside: an arsenal of sophisticated surveillance and tracking equipment powerful enough to read license plates - or scan pedestrians' faces - from high above the nation's largest metropolis. "It looks like just another helicopter in the sky," said Assistant Police Chief Charles Kammerdener, who oversees the department's aviation unit. Police Commissioner Raymond Kelly has said that no other U.S. law enforcement agency "has anything that comes close" to the surveillance chopper, which was designed by engineers at Bell Helicopter and computer technicians based on NYPD specifications. The $10 million helicopter is just part of the department's efforts to adopt cutting-edge technology for its [surveillance] operations. The NYPD also plans to spend tens of millions of dollars strengthening security in the lower Manhattan business district with a network of closed-circuit television cameras and license-plate readers posted at bridges, tunnels and other entry points. Civil rights advocates are skeptical about the push for more surveillance, arguing it reflects the NYPD's evolution into ad hoc spy agency.