“Senior US administration officials…said that after 9/11 the CIA chased various leads about Bin Laden’s inner circle, in particular his couriers. One of these couriers came in for special attention, mentioned by detainees at Guantánamo Bay by his nom de guerre. He was said to be a protege of Khalid Sheikh Mohammed, the 9/11 mastermind, and one of the few couriers Bin Laden trusted. Officials said they were initially unable to identify him but finally did so four years ago. …Two years ago, the CIA found the rough location where the courier and his brother lived in Pakistan, and in August last year they narrowed it down to a compound in Abbottabad… They realised immediately this was no normal residence. The walls of the 3,000 sq ft compound were 12-18ft high, topped with barbed wire. There were two security gates, and access to the compound was severely restricted. The main part of the residence was three storeys high but had few windows, and a third-floor terrace was shielded by a privacy wall. Built around five years ago, it was valued at about $1m but had no phone or internet connection. The two brothers had no known source of income, adding to CIA suspicions. The CIA learned too that there was a family living with them, and that the composition of this family matched Bin Laden’s.

 – Ewen MacAskill, “Osama bin Laden: it Took Years to Find Him but Just Minutes to Kill Him,” The Guardian, May 2, 2011