For CIA, bin Laden's courier was key link

>>> well, good evening once again here. and we are back with our special extended coverage of the death of osama bin laden and some of the other news of this day. as we said at the top of our first half hour here tonight, new details are emerging about this daring raid that brought down bin laden in pakistan. the story changing a bit as what they call the fog of war , or at least this raid, starts to clear. we want to go right to the pentagon and nbc news pentagon correspondent jim miklaszewski . and jim, from your perspective, how did details change today?

>> reporter: well, brian, in terms of the details, we heard from the white house that they were actually changing the story about some of the events that occurred inside that compound. particularly when it came to the shooting of osama bin laden . initially, the white house said he was armed. then they said he was unarmed. and today we learned that his wife actually charged a navy s.e.a.l., who then shot her in the leg before he shot osama bin laden twice. you know, but overall, this journey, the kind of intelligence gathering to get osama bin laden , took years. and there were a few lucky breaks along the way. for more than 15 years osama bin laden was america's most wanted. but in the end it was a lowly courier that brought down the world's most notorious terrorist. u.s. officials tell nbc news the original tip came unwittingly from 9/11 mastermind khalid sheikh mohammed and abu farraj al libi while both were in cia custody. under aggressive interrogations both denied that they knew bin laden 's trusted courier, raising suspicions that courier was the closest link to the al qaeda leader.

>> we got incredibly valuable data after we interrogated suspects. different question about whether the american people think they're appropriate. but the data i saw were hugely valuable.

>> reporter: then last july came the first big break . cia operatives tracked down the courier on the streets of peshawar, pakistan and eventually trakds him to this massive compound 35 miles north of islamabad. from then on the compound was under heavy cia and satellite surveillance. and although bin laden himself was never spotted, intelligence officials became convinced he was there.

>> putting this together was not an easy feat. it meant a sustained analysis over a substantial period of time.

>> reporter: last friday president obama considered the intelligence compelling enough to order the attack on sunday. half past midnight , three u.s. helicopters flying low under pakistani radar zeroed in on the compound. one helicopter was forced to land inside a courtyard, clipping a wall with its tail rotor. back at the white house the president and his national security team were riveted to a live video feed of the operation. as dozens of u.s. commandos set up a perimeter, two teams of assault forces, delta force and navy s.e.a.l.s, stormed the compound. as one commando entered a third-floor bedroom, he came face to face with osama bin laden , who was unarmed. but bin laden 's wife charged straight at the american, who shot her in the leg. he then fired two rounds at bin laden , one in the face, one in the chest, and the al qaeda leader fell dead. the white house today struggled to explain why bin laden was shot when he was unarmed.

>> there were many other people who were armed in the region -- i mean in the compound. there was a firefight.

>> reporter: 40 minutes after they landed u.s. forces took off with the body of bin laden , destroying the disabled helicopter on the way out. the commandos also gathered a potential mother lode of intelligence. five computers, ten hard drives , and more than 100 disks and thumb drives . a special cia task force has already started searching the material for al qaeda secrets bin laden may have left behind. and while the white house is still struggling over whether to release photos of a deceased osama bin laden , the administration is expected to release photos and perhaps even a video of bin laden 's burial at sea in an effort to prove that at least was a respectful ceremony. brian?

>> all right. all of it apparently developing. jim miklaszewski from the pentagon again tonight. jim,