- Suicide bomber who killed six U.S. service members packed explosives inside his motorcycle
- Americans were walking in a contained area, making blast more powerful because it did not disperse
The U.S. troops were on a security patrol outside Bagram Airfield. Typically, patrol missions require troops to walk with space between individuals in order to prevent mass casualties in the event of a suicide attack.
The attack happened after the motorcycle driver passed through an initial perimeter of Afghan security. It appears, according to the U.S. 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.
A senior U.S. military official told CNN it is not unusual for such personnel 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.
The bodies of the six Americans were flown home Wednesday. Their flag-draped caskets arrived at New Castle Air National Guard Base in Delaware for dignified transfer.