The US investigators will scrutiny the sea of intelligence materials seized from the Abbottabad compound,where Osama bin Laden was killed,as a the CIA described the haul as a "small college library." "This is the largest cache of intelligence derived from the scene of any single terrorist," national security adviser Tom Donilon told NBC. "It's about the size,the CIA tells us,of a small college library," he said. Navy SEALs on Monday raided bin Laden's walled compound in Abbottabad in Pakistan and killed him,and his body was buried at sea. The investigations have shown that Osama was actively involved in planning and directing al-Qaida's terror plots. "What we now know,again taking a look initially here,is that he had obviously an operational and strategic role,and a propaganda role,for al-Qaida," Donilon told CNN. Computer material gathered by the US forces after the pre-dawn raid revealed bin Laden's Abbottabad home was a command-and-control centre for al-Qaeda,said a senior US intelligence official.