Washington ( CNN ) -- President Barack Obama gave the go-ahead for U.S. forces to raid a northern Pakistan housing compound based on `` what was probably a 50-50 chance that Osama bin Laden was there , '' his national security adviser said . `` It was a circumstantial case ... But what he had 100 percent confidence in was the ability of our special forces to execute the mission , '' Tom Donilon told CNN 's Candy Crowley on Saturday , part of an interview that aired Sunday on `` State of the Union . '' On April 28 , Obama attended the last of several National Security Council meetings focused on finding and going after the al Qaeda leader . During that meeting , some advocated for the commando raid while others advised against it , Donilon said , given there had been no clear-cut sightings of bin Laden by that point . `` He had gotten divided counsel , and that happens a lot in these things , as you would imagine , '' Donilon said . After a night 's sleep , Obama told Donilon at 8:20 a.m. the next day to draft the order for the raid . By Sunday evening -- which was early Monday morning in Pakistan -- the 38-minute mission was over , the 25-strong U.S. team having flown out of the country along with bin Laden 's dead body . Like other Obama administration officials , Donilon applauded the decision and its end result of knocking out the No . 1 man on the FBI 's `` Most Wanted Terrorist '' list . He called it `` the single biggest achievement we 've ever had '' in the fight against al Qaeda . Especially as they continue poring through voluminous material taken from the complex , U.S. authorities are more convinced than ever that bin Laden had a significant operational and strategic role , not to mention a key symbolic one , in the terrorist network . His death , said Donilon , is a major blow to al Qaeda . `` At the end of last year , we assessed that al Qaeda had been diminished ... to its weakest since 2001 , '' said the security adviser , who previously served in the administrations of presidents Jimmy Carter and Bill Clinton . `` And they took a very big step back Sunday . '' One reason for that assessment is what Donilon called the `` extraordinary '' amount of intelligence that U.S. special forces were able to take from the Abbottabad compound . A multi-agency task force is currently poring through those documents , computer hard drives and other materials -- intermittently releasing information including five videotapes featuring bin Laden that came out Saturday . `` This is the largest cache of information gotten from a senior terrorist -- gotten from any terrorist in one operation , '' Donilon said , calling the amount of seized material about equal to `` the size of a small college library . '' Despite doubts from some conspiracy theorists , al Qaeda itself has admitted that bin Laden was killed . That means that his deputy , Egyptian doctor and radical Ayman al-Zawahiri , will rise to the top of the FBI list , according to Donilon , even as U.S. and allied forces continue their efforts to find him and other al Qaeda leaders . Last week , CIA Director Leon Panetta ( who Obama has nominated to succeed Robert Gates as defense secretary ) told House members during a closed-door briefing that Pakistan was `` either involved or incompetent , '' according to two sources in attendance . There have been no indications Pakistani authorities knew about or acted upon knowledge that bin Laden was living in the same town as one of its top military academies . Donilon did not suggest Pakistani authorities knew the al Qaeda leader lived in the city , about 30 miles ( 50 kilometers ) north of the capital Islamabad , or that they somehow harbored him . He said , `` I have not seen any evidence , at least to date , that the political , military or intelligence apparatus knew about the presence of Osama bin Laden . '' Yet U.S. authorities are troubled by the fact that the al Qaeda leader could stay there `` for six years or so '' undetected , said Donilon . `` We 'll clearly be working with ( Pakistani authorities ) to understand how we got to this point , '' he said . Donilon noted Pakistan 's active role in tracking down terrorists , calling them a `` very important partner '' despite the existence of some `` differences '' with U.S. authorities . He said , `` If we find things ... that are highly disturbing , we 'll certainly press that '' -- though he expected that Islamabad and Washington would continue to work together . `` We need to look at this in a calm and cool way , '' Donilon said , adding , `` a relationship with Pakistan , given everything we have at stake in that region , is an important relationship . ''
National Security Adviser Tom Donilon says Obama got `` divided counsel '' on raid . Relying on a `` circumstantial case , '' the president gave the go-ahead the next morning . Donilon says the amount of intel gathered is `` about the size of a college library '' He says there 's no evidence Pakistani authorities knew that bin Laden was there .