Exclusive: CIA Attacker Driven in From Pakistan

KABUL, Afghanistan, Jan. 2, 2010— -- The suicide bomber who killed at least six Central Intelligence Agency officers in a base along the Afghan-Pakistan border on Wednesday was a regular CIA informant who had visited the same base multiple times in the past, according to someone close to the base's security director.

The informant was a Pakistani and a member of the Wazir tribe from the Pakistani tribal area North Waziristan, according to the same source. The base security director, an Afghan named Arghawan, would pick up the informant at the Ghulam Khan border crossing and drive him about two hours into Forward Operating Base Chapman, from where the CIA operates.

Because he was with Arghawan, the informant was not searched, the source says. Arghawan also died in the attack.

The story seems to corroborate a claim by the Taliban on the Pakistani side of the border that they had turned a CIA asset into a double agent and sent him to kill the officers in the base, located in the eastern Afghan province of Khost.

The infiltration into the heart of the CIA's operation in eastern Afghanistan deals a strong blow to the agency's ability to fight Taliban and al Qaeda, former intelligence officials say, and will make the agency reconsider how it recruits Pakistani and Afghan informants.

The officers who were killed in the attack were at the heart of the United States' effort against senior members of al Qaeda and the Taliban, former intelligence officials say. They collected intelligence on the militant commanders living on both sides of the border and helped run paramilitary campaigns that tired to kill those commanders, including the drone program that has killed a dozen senior al Qaeda with missiles fired from unpiloted aircraft.

The former intelligence officials all say the CIA will be able to replace those who were killed, but the officials acknowledge the attack killed decades of knowledge held by some of the agency's most informed experts on the region, the Taliban and al Qaeda. It also killed at least one officer who had been part of the agency's initial hunt for Osama bin Laden in the mid-1990s.