An American major was killed and three American officers were wounded, along with their Afghan interpreter, in what fresh accounts from the Afghan and American officers who were there reveal was a complex, calculated assault by a nominal ally. The Pakistanis opened fire on the Americans, who returned fire before escaping in a blood-soaked Black Hawk helicopter…

The details of the ambush indicate that Americans were keenly aware of Pakistan’s sometimes duplicitous role long before Adm. Mike Mullen, the chairman of the Joint Chiefs of Staff, told the Senate last week that Pakistan’s intelligence service was undermining efforts in Afghanistan and had supported insurgents who attacked the American Embassy in Kabul this month.

Though both sides kept any deeper investigations of the ambush under wraps, even at the time it was seen as a turning point by officials managing day-to-day relations with Pakistan…

At first, the meeting to resolve the border dispute seemed a success. Despite some tense moments, the delegations ate lunch together, exchanged phone numbers and made plans to meet again. Then, as the Americans and Afghans prepared to leave, the Pakistanis opened fire without warning. The assault involved multiple gunmen, Pakistani intelligence agents and military officers, and an attempt to kidnap or draw away the senior American and Afghan officials.