AP Photo

In the weeks following the Sept. 11, 2001, terrorist attacks against the United States, journalists scattered across northern Afghanistan would periodically gather in a mud-walled compound in the small and sand-blown village of Khwaja Bahauddin to attend press conferences hosted by a well-dressed ophthalmologist with thin hair brushed straight back from his forehead and a close-trimmed black beard.

His English was flawless and devoid of slang or colloquialisms. Years earlier, during the anti-Soviet Afghan jihad, he had been taught English by agents in Britain’s MI6 foreign intelligence service. He was patient with the questions thrown at him, but his back seemed to stiffen when asked how much the Americans and British were sharing intelligence they...