CNN has learned the suicide bomber that killed six U.S. Air Force personnel in Afghanistan this week was likely able to inflict catastrophic damage by packing explosives inside the internal spaces of an old motorcycle, rather than simply wearing a suicide vest, according to a U.S. official familiar with the latest information about the incident.
The U.S. troops were on a security patrol outside Bagram Airfield, which is a mission that usually requires troops to walk with space between individuals just so suicide attacks do not inflict mass casualties.
The attack happened after the motorcycle driver passed through an initial perimeter of Afghan security. It appears, according to the official, that the Afghans did not detect the bike itself was internally packed with explosives. It then approached the troops who were outside and detonated.
Because the Americans were walking in a narrow lane surrounded by walls, the blast bounced off the walls, rather than dispersing, and the power was contained in a relatively small area. The bomb material was small metal balls that dispersed at a high velocity in that contained area, the official said.
Four of the personnel were part of the Air Force Office of Special Investigations, which conducts civil and criminal investigations for the Air Force. But a senior U.S. military official tells CNN it is not unusual for them to undertake security patrols. The patrol had been sent out to talk to local Afghans outside Bagram in part because there are several villages so close to the base, a major area for U.S. military operations. The patrols are also conducted so U.S. personnel can gather intelligence to keep rockets and mortars from being fired at the base.