Spectacular tale from the AP:

Again and again, John and his team asked themselves who else might be living in that compound. They came up with five or six alternatives; bin Laden was always the best explanation.

This went on for months. By about February, John told his bosses, including Panetta, that the CIA could keep trying, but the information was unlikely to get any better. He told Panetta this might be their best chance to find bin Laden and it would not last forever. Panetta made that same point to the president

Panetta held regular meetings on the hunt, often concluding with an around-the-table poll: How sure are you that this is bin Laden?

John was always bullish, rating his confidence as high as 80 percent.

Others weren’t so sure, especially those who had been in the room for operations that went bad.