"We do not rely only on what people say immediately after a battle. Our investigators follow up afterward, talk to village elders, to families, and look at fresh graves," De Beer said. "When there is any question of identity, we take that into account."
Often, civilians are killed in the aftermath of an attack by insurgents. Azizullah was shot and killed by troops responding to a car bomb that went off about half a mile away.
The NATO-led force said at the time that initial indications were that a soldier's weapon had accidentally discharged. Two weeks later, a spokesman said there had been no further findings.
Azizullah's family, an extended clan of 25 living in a mud-brick compound on the outskirts of the capital, veered between mourning and fury.
"Who will bring my son back to me?" asked his weeping, white-turbaned father, Mohammed Zia. "No one, no one. Not even God."
The family was particularly angered by the fact that the shooting took place more than an hour after the explosion and that there was no report of hostile fire directed at troops.
"We thought the foreign troops, the Americans, would bring peace to this country," said the father. "Now they have killed my son, and I do not want to see their faces ever again."
Political analysts say that despite the increase in civilian deaths, most Afghans still support the presence of international troops.
"It's an obvious truth that the Western forces bring security that we need," said Said Najib Mahmood, a political science professor at Kabul University. "But they are killing a lot of people, and because of that there is a loss of trust and confidence in the government."
Many analysts say the nature of combat tactics employed by both sides makes it very difficult for the military to avoid inflicting civilian casualties, a fact that the Taliban movement exploits to the maximum.
When allied forces come under fire from a walled compound of the kind that dots every Afghan village, the likeliest response is an airstrike -- a strategy that exposes Western troops to less danger than moving in on foot.
Sometimes, even hours of painstaking surveillance fail to turn up signs of noncombatants in the line of fire.
"Often we will refrain from making a strike because we suspect there might be civilians present," said Thomas. "But sometimes we're wrong."
If so, the consequences can be devastating.
