As the CIA homed in on al-Kuwaiti, John’s team continually updated the memo with fresh information.

Everyone knew that anything with bin Laden’s name on it would shoot right to the director’s desk and invite scrutiny, so the early drafts played down hopes that the courier would lead to bin Laden. But John saw the bigger picture. The hunt for al-Kuwaiti was effectively the hunt for bin Laden, and he was not afraid to say so.

The revised memo was finished in September 2010. John, by then deputy chief of the Pakistan-Afghanistan Department, emailed it to those who needed to know. The title was “Anatomy of a Lead.”

As expected, the memo immediately became a hot topic inside CIA headquarters and Director Leon Panetta wanted to know more. John never overpromised, colleagues recall, but he was unafraid to say there was a good chance this might be the break the agency was looking for.

The CIA tracked al-Kuwaiti to a walled compound in Abbottabad. If bin Laden was hiding there, in a busy suburb not far from Pakistan’s military academy, it challenged much of what the agency had assumed about his hideout.