What happened in the takedown of Osama bin Laden was the pinnacle of years of intelligence work which included the CIA, the NGA, and the NSA, according to White House senior administration officials' reports which chronicle the details below:
It began with the CIA following leads on those bin Laden considered his closest. Detainees post-9/11 gave information on individuals who had been directly aiding bin Laden and his deputy after they left Afghanistan.
The detainees turned over one courier's nickname who featured a repulsive resume: he was the student of Khalid Sheikh Mohammed and an assistant to Al Qaeda's former number 3, Abu Faraj al-Libbi. Even more important, this courier was one of few trusted by bin Laden and possibly was living with him and protecting him.
For years, however, the courier's real name and location remained a secret from the U.S. Then, four years ago, his name was discovered. Two years later, the U.S. also discovered his areas of operation in Pakistan, though his living quarters eluded U.S. intel, which in itself was a further indication to the U.S. that they were pursuing something worthwhile.
In August 2010, that home was finally discovered. It's interesting to note that the White House report describes the area as somewhat affluent and a place with much retired military. Khalid Sheikh Mohammed and Al Qaeda's #3 were also captured in settled areas of the country. The sight of the 3-story, $1 million living residence surprised the U.S.: it was on a large area of land, approximately eight times larger than the other residences there. It had 12 to 18-foot walls with barbed wire perched on top. It also had internal wall sections. Those who lived there reportedly burned their trash (unlike their neighbors, who put the trash out to be picked up), and the compound's entrances were two security gates. The 3rd floor terrace had a 7-foot privacy wall. It also had no internet or telephone service connected. The courier (and his brother) did not have an "explainable source of wealth." At the time it was built (2005), it was relatively isolated, but other homes have since built up close by.
Then U.S. intelligence discovered there was another family living in the compound in addition to those of the two brothers. This family fit the description consistent with that which the U.S. expected would be accompanying bin Laden.
But the U.S. wanted to be sure, so it conducted red team exercises and analyzed the intel from every angle. The results consistently pointed to the secret inside the compound being Osama bin Laden.