is the bomb squad, radiation detection, network of camera systems, the explosive detection dogs, the biohazard detection devices, or the intelligence bureau which is the investigations, the sources of information. >> layer 1, office was armed with long guns visible to the public regarding the tower. together with the secret service the counterterrorism trigger critical response command has every step covered. layer 2, not so visible nypd counter sniper teams. and we got an exclusive behind the scenes look at how they train using a magnified -- on an assault rifle. >> 200 yards, the magnified scope allows us to center our target and a 200 yards just as if it was 25 feet away. we prepare everything from the situations so we would take the 200 yard shot, anything from a