• DIGITAL STILL AND VIDEO CAMERAS fitted with large telephoto lenses make it possible for agents to discern the details of a faraway scene. An operative wielding a telephoto camera can read a newspaper headline (and, perhaps, subheads) from a football field’s length away.
  • NIGHT-VISION GOGGLES or telescopes fitted with photomultiplier tubes can dramatically brighten available light; thermal sensors can reveal warm bodies and hot engines in total darkness.
  • VOICE, facial features, walking gait and other characteristics can identify a person whose physical or behavioral traits are registered in an existing database.
  • DNA SENSOR, one of the latest biometric systems, samples DNA left, say, on a glass or doorknob and compares it with genetic information on file.
  • ARTIFICIAL NOSE detects a subject’s body “odor print,” which is matched against records.
  • DIRECTIONAL MIKE, assisted by a parabolic dish or a “shotgun” (linear wand), can pick up open-air conversations from several hundred feet away.
  • BUG, a tiny, hidden microphone and short-range radio transmitter, sends conversations to a radio receiver, which relays the speech to a recorder or headphones.
  • LASER BEAM bounced off a window can detect vibrations of the glass produced by the sounds of indoor conversations. An optical receiver converts patterns in the reflected beam into sounds a snoop can hear.
  • CHEMICAL MARKERS placed at a site attach to subjects when they touch or step on them.
  • GPS LOCATOR receives signals from the Global Positioning System and pinpoints a vehicle’s or person’s location to within six feet.
  • ELECTRONIC TOLL TAKERS, such as E-ZPass, enable authorities to monitor vehicles as they pass checkpoints.
  • PHONE TAP is a set of wires spliced into a junction box or phone line. Part of the signal branches into the tap, making remote listening possible.
  • COMPUTER TAPS, techniques that intercept e-mail, overhear voice communications or “sniff” keystrokes, permit spying on computer operations.
  • CELL PHONE MONITOR, a radio receiver tuned in to cell phone frequencies, enables agents to listen in on wireless calls.
  • DISCARDED PHONE BILLS, credit-card statements and computer hard drives can reveal a subject’s sensitive information.
  • AIRPLANES, unmanned aerial vehicles and satellites can monitor targets from above. The U.S. KH-11 spy satellite reportedly has a maximum image resolution of less than six inches; newer, still secret orbital surveillance systems may perform even better.
  • SMALL SPY DEVICES, equipped with surveillance gear, may soon fly or walk into sites of interest under remote control.

Note: This story was originally printed with the title, "Tools of the Spy Trade".