in the years after tora bora, bin laden seems to have vanished, appearing only in video messages that mysteriously materialize, but leave no trace of his whereabouts. general michael hayden headed up the cia at the time. for most of my time in office, i would even publicly say the trail was quite cold. we didn t have a lot of evidence in which we had much confidence. reporter: tough interrogations of al qaeda detainees, some at secret prisons, begin to provide the clues that will lead to a compound in pakistan, the mansion hideout of osama bin laden. we began to focus, drill down on the courier network as
reporter: in the years after tora bora, bin laden seems to have vanished, appearing only in video messages that mysteriously materialize, but leave no trace of his whereabouts. general michael hayden headed up the cia at the time. for most of my time in office, i would even publically say that the trail was quite cold. we didn t have a whole lot of evidence in which we had much confidence. reporter: tough interrogations of al qaeda detainees, some at secret prisons, begin to provide the clues that will lead to a compound in pakistan, the mansion hideout of osama bin laden. we began to focus, drill down on the courier network as perhaps a way to chase after bin laden.
mansion hideout of osama bin laden. we began to focus, drill down on the courier network as perhaps a way to chase after bin laden. we knew he was communicating, but we were convinced he could not possibly be communicating electronically or we would have picked that up. it had to be human-to-human contact, hence the courier system. amongst people detained soon after tora bora were ahmad al-katani. he tried to be the 20th hijacker but he was never admitted to the united states. reporter: according to this interrogation log obtained by time magazine the would be 9/11 hijacker doesn t give up information easily at guantanamo bay so they subject him to standing nude and having pictures of nude women hung around his neck.
reporter: in the years after tora bora, bin laden seems to have vanished, appearing only in video messages that mysteriously materialize, but leave no trace of his whereabouts. general michael hayden headed up the cia at the time. for most of my time in office, i would even publically say that the trail was quite cold. we didn t have a whole lot of evidence in which we had much confidence. reporter: tough interrogations of al qaeda detainees, some at secret prisons, begin to provide the clues that will lead to a compound in pakistan, the pan mansion hideout of osama bin laden. we began to focus, drill down on the courier network as
failure, high. would rather die than be captured. at the end of the day it was a leap of faith. reporter: friday, april 29th, just after 8:20 a.m., the mission begins. the president gives the go. the president, after a long night s sleep, he basically came in and immediately told his staff you have the green light. let s go. reporter: as president obama departs for the tornado-ravaged south, the u.s. military s best-kept secret is underway. the troops were ready and in place. the equipment was ready to go. the plan had been practiced again and again and again. reporter: america s most-wanted man may finally be in reach, osama bin laden. the architect of 9/11 had eluded the world s most powerful nation for more than a decade. the trail was quite cold. reporter: former cia director michael hayden recalls the early misfires. most of what we had looked many more like elvis sightings rather than substantive intelligence. u.s. intelligence zeroed in on this co