It put him so close to the center of power in Afghanistan that he was just paces away from Gen. Austin S. Miller, the commander of United States and NATO forces, when he suddenly raised his Kalashnikov and started firing in bursts.

The attack was a nightmare scenario for American and Afghan security planners: a Taliban operation months in the making that succeeded in breaching a high-level meeting, killing a powerful Afghan general and a provincial intelligence chief, wounding an Afghan governor and an American general — and barely missing General Miller and other officials standing nearby.

The infiltration and the chaotic American escape two weeks ago — detailed in interviews with more than a dozen people, including witnesses, family members and officials who have seen investigative reports — have deeply shaken the relationship between Afghan and American forces.