An Afghan informant was without any of the searches that would have detected explosives, reports CBS News correspondent David Martin. He walked up to where more than a dozen CIA operatives had gathered for a meeting and detonated his suicide vest.
According to former CIA Counterterrorism Chief Bob Grenier it was the Taliban equivalent of a precision guided weapon.
"The fact that this individual apparently penetrated as deeply on that base as he did, the fact he was able to get access to the individuals that he did suggests that this was not only his intent, but there must have been some sort of trusted relations with that individual," Grenier said.
The CIA is keeping the identities secret but one of the dead, , was a mother of three. Six other agency employees were gravely wounded.
Located on the border with Pakistan, Camp Chapman was used as a base for recruiting spies who, according to former CIA officer Gary Berntsen, would be sent to pinpoint targets for commando raids and air strikes.
"Collection would take place on both sides of the border in an effort to identify leadership targets within the Taliban and key al Qaeda targets," Berntsen said.
Officials credit the base with providing some of the intelligence which has enabled CIA drone strikes to eliminate much of al Qaeda's top leadership. It is a vicious game in which anyone suspected of spying for the Americans is executed and someone forgot the most basic rule of espionage.
"You can never be sure that you can trust anyone and the individual that you can trust today you may not be able to trust tomorrow," Grenier said.
With seven dead and six wounded, that base has now been knocked out of action until the CIA can send in a new team of operatives.