At a checkpoint leading to the U.S.-protected Green Zone, Gordy stands sentry. The affable Belgian Malinois has a nose finely tuned to detect the nitrates, plastic explosives, gunpowder and detonation cords that suicide bombers use to blow up people. On a barren stretch of road in northern Iraq, a dog rigged with explosives approaches a group of Iraqi police officers. Detonated by remote control, the bomb tears the dog apart but doesn't harm the cops.