The slain leader was developing a wider terror network, particularly in Europe.
American investigators are exploiting the intelligence bonanza found in the rural safe house north of Baghdad where Abu Musab al-Zarqawi, the leader of Al Qaeda in Iraq, was killed last Wednesday.
Analysts say that the memory sticks, hard drives, and documents found there and at some 56 other sites raided after the Jordanian militant's death are likely to damage Mr. Zarqawi's networks. The US military describes the finds as a "treasure trove."
The new intelligence leads could uncover terrorist operations far afield from Iraq - particularly in Europe - as Zarqawi had begun to piece together a much wider network of militants, experts say.
"The US government will have a firm understanding of Zarqawi's network, not only in Iraq, but Zarqawi's global network," says Rohan Gunaratna, a terrorism expert at the Institute of Defence and Strategic Studies in Singapore. "Zarqawi had penetrated at least 20 European countries, Canada, ... and even established cells in Southeast Asia."
Some say the scale of Zarqawi's operations - bolstered by recruits inspired by his battlefield exploits in Iraq - may have begun to rival the less visible Osama bin Laden.
"Zarqawi was building a global terror network parallel to Al Qaeda of bin Laden," says Mr. Gunaratna, who is also author of "Inside Al Qaeda." "The killing of Zarqawi is a huge victory - not so much against the Iraqi insurgency, because the insurgency will continue, [but] internationally.... And this network will suffer."
Zarqawi's followers vowed to fight back Sunday with "major attacks" in Iraq, and to renew their "allegiance" to Al Qaeda chief, Mr. bin Laden. An Internet statement said the leadership of Zarqawi's Al Qaeda in Iraq met after his death, and promised to "prepare major attacks that will shake the enemy like an earthquake."
The group - posting its message on a site used by the umbrella Mujahideen Shura Council - did not name a successor to Zarqawi.
Depending on what media survived the bombs and the caliber of the more than two-dozen suspects detained in the raids, the information could potentially be in league with that gleaned from the fall of Kabul in 2001 or the capture of Al Qaeda operational mastermind Khalid Sheikh Mohammed in Pakistan in 2003, experts say.