"This intelligence case is different. What we see in this compound is different from anything we've ever seen before," said John Brennan, White House counterterrorism advisor.

It was a $1 million compound, eight times bigger than any of the other homes, in a town where retired Pakistani military officers live, just 35 miles north of the capital of Islamabad. 

It was built in 2005, apparently just for bin Laden, with walls as high as 18 feet, topped with barbed wire, the main building with opaque windows facing out and a seven-foot privacy wall on the third floor balcony. The residents of the compound burned their trash instead of putting it out for collection and despite the $1 million price tag, there was no telephone or internet service. Three families lived there: the courier's family, his brother's family, and a third family about the size of bin Laden's. It was a convincing but circumstantial case.

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Pictures: Osama bin Laden
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Once US had located the compound where the courier lived, they put it under surveillance and noticed that every day a tall man emerged from the main house and walked for an hour around the courtyard. Imagery indicated that the man was between 5'8" and 6'5", but the photos were not good enough to make a positive identification. They were images from satellites and not drones, since location was too risky to deploy the unmanned aircraft.