Next target: Zarqawi's global web

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.

"There is a pattern of senior associates of Al Qaeda, that they keep so much information, so much data - they like to have everything close to their chest, and have it with them," says Michael Radu, the co-chair of the Center on Terrorism at the Foreign Policy Research Institute in Philadelphia.

Zarqawi's network, especially in Europe, "is much more extensive than that of bin Laden or [Al Qaeda No. 2, Ayman] al-Zawahiri," says Mr. Radu. "I wouldn't be surprised if we see another wave of arrests in Europe. Then we will know if what was captured [in Iraq] and after was indeed important for [Zarqawi's] network."

Jordanian security officials estimate that Zarqawi recruited, trained, and sent back 300 militants, who are now awaiting orders in their home countries to strike, according to a report in Sunday's edition of The New York Times.

The US military in Baghdad is not further describing the contents or value of the Zarqawi material, says spokesman Maj. Douglas Powell, because "the intelligence is still being developed and we're not ready to address anything specific." Maj. Gen. William Caldwell says he is pushing to have some information quickly declassified.

US forces have "had a steady drum beat of operations against the Al Qaeda network here in Iraq since the Zarqawi operation," Gen. George Casey, commander of multinational forces in Iraq, told Fox News on Sunday. "We will continue to go after [Zarqawi's] network and disrupt it in what we feel is a very vulnerable period. And so we hope to take advantage of that."

Zarqawi's top followers will assume that US forces are exploiting the new leads, says Gunaratna. "Some key operatives will change their venue and their methods," he says. "They will know that Zarqawi's material has been compromised."

The ultimate value of the intelligence from "such a big event" as last week's raids "depends on how [Zarqawi's network is] organized. The goal is always to cut off the head," says a US official in Baghdad familiar with terrorism investigations.

"Think about it like a corporation. The little guy is going to have information about his boss, who will know about the subdivision - the best thing is to get them all," says the official. "But not everybody is organized that way; it is not necessarily a hierarchy."

Indeed, Zarqawi's network appeared to operate alongside - not necessarily over - a broader Iraqi insurgency. Last January Zarqawi helped form the Mujahideen Shura Council, bringing together several Sunni insurgent groups that share Al Qaeda's ideology of turning Iraq into an Islamic state.

"His Shura Council is 80 percent Iraqi, so [US and Iraqi forces] will continue to hunt those people," says Gunaratna. "But Zarqawi has made this group very Iraqi. He has seeded his ideas and values to those Iraqis."

Indeed, Zarqawi's adherents seem to be working on revenge. A string of attacks have continued unabated in Baghdad and elsewhere in Iraq, killing an average 19 people a day over the past three days.

Also Saturday, a more prescient clue: a gruesome video on the Internet of the beheading of three uniformed Shiites, that were claimed in the video to be members of a death squad - a tactic often used by Zarqawi himself against Western hostages.

"Iraq is the front defense line for Islam and Muslims, so don't fail to follow the path of the mujahideen [holy warriors], the caravan of martyrs and the faithful," said Abdullah Rashid al-Baghdadi, the Iraqi leader of Council.

"As for you, the slaves of the cross [Christian coalition forces], the grandsons of Ibn al-Alqami [Shiites], and every infidel of the Sunnis, we can't wait to sever your necks with our swords," warned Mr. Baghdadi, according to an Associated Press translation of the Internet statement.

But the ability of Zarqawi's acolytes to produce and disseminate such videos also may prove to undermine such technically savvy groups.

"They have to keep track of all these little cells they have, and contacts. And the fact that so many have computer training is a temptation to put everything on a hard drive, because who can memorize all those individuals and aliases?" says Radu, of FPRI, about Al Qaeda leaders. "The electronic age is a double-edged sword for them, because it makes them vulnerable if those things are captured."