New evidence of the way Islamic terrorists evade detection by operating in loosely connected networks is emerging from the investigation of the Madrid bomb attacks.
Eleven days after the atrocity in the Spanish capital, the ties that are emerging between a key suspect in the bombing and Islamic militants elsewhere in Europe and North Africa point to a widening web of organizations that may have few direct links to Al Qaeda but are bent on the same goals.
The investigation has also revealed how terrorist plotters from different structures appear to have survived police crackdowns in several countries to regroup and join forces in order to carry out the operation in Madrid, which killed 202 people.
The attack has revealed "an accumulation of strata from different networks that had been damaged but which managed to fuse, a patchwork of leftovers" that re-generated itself, says Jean-Charles Brisard, a former French secret service agent now investigating Al Qaeda for lawyers representing relatives of 9/11 victims.
That fusion illustrates how "the threat of terrorism has shifted from Al Qaeda to associated organizations" inspired by Osama bin Laden without necessarily waiting for his orders, says Rohan Gunaratna, author of "Inside Al Qaeda: Global Network of Terror." "Al Qaeda has become a movement, it is no longer a single group."
The key, Dr. Gunaratna argues, is closer international cooperation among intelligence services. "European security services are still looking at terrorist networks as national problems," he says. "They have not matched the integration Al Qaeda has achieved in combining networks."
European interior ministers decided at an emergency meeting in Brussels on Friday to name an antiterrorism "czar" to coordinate activities across the European Union. Intelligence agency chiefs from Britain, France, Italy, Germany, and Spain are scheduled to meet Monday in a bid to spur closer cooperation among them.
The scale of the challenge they face has become clearer from patterns that investigators have discerned in the wake of the Madrid bombings, leading them in several directions across Europe and North Africa as they follow links that the central suspect, the Moroccan Jamal Zougam, may have forged with Islamic militants.
Spanish police tapped a phone call that Mr. Zougam made in August 2001 to Imad Eddin Barakat Yarkas, currently jailed in Spain following his indictment last year by judge Balthazar Garzon, who suspects him of having been the head of Al Qaeda's cell in Spain.
Zougam was heard to say he had met and offered financial aid to Mohamed Fizazi. Mr. Fizazi is believed to be the spiritual leader of Salafiyah Jihadiyah, a Moroccan extremist group. He was found guilty by a Moroccan court last year of involvement in May's suicide bombings that killed 44 people in Casablanca, and was jailed for 30 years.
Zougam had come under investigation by the Spanish police at the request of the French authorities, who had found his name in an address book belonging to David Courtailler, a French convert to Islam who went on trial in Paris last week on charges of terrorist association. Mr. Courtailler's brother, Jerome, was acquitted in 2002 of plotting an attack on the US embassy in Paris. David Courtailler once shared an apartment with Zacharias Moussaoui, the only person so far charged in the United States in connection with the World Trade Center attack.
Zougam also visited Mullah Krekar, an Iraqi Kurdish exile, according to Judge Garzon's 600,000 page investigation of Al Qaeda activities in Spain. Mr. Krekar founded the Kurdish group that became Ansar al-Islam and is accused by US intelligence officials of ordering attacks on US troops in Iraq.
Among alleged terrorist leaders believed to have worked with Ansar al-Islam is Abu Musab Zarqawi, founder of the Jordanian radical Islamist Al Tawhid group, which German police have said is now active among Middle Eastern exiles in Germany and Italy, seeking recruits to fight US forces in Iraq and planning attacks in western Europe.
Groups such as Ansar, the Salafists, al-Tawhid, and others like them around Europe, North Africa. and the Middle East are loosely federated in the "World Islamic Front for Jihad Against Jews and Crusaders," which Mr. bin Laden set up in 1998, says Gunaratna. But they act on their own initiative, drawing on their members' personal connections as necessary.
"The ones who give orders are harder to identify," says Mr. Brisard. "As the Al Qaeda leadership has suffered, new more local, regional leaders have sprung up."
These leaders - and the plotters they command - are not always invisible, and western intelligence agencies have scored some notable successes.
Among an estimated 20 or so planned Islamist terrorist operations in Europe that have been thwarted in recent years were plots to blow up a Christmas market in Strasbourg, to attack Western shipping in the Straits of Gibraltar, to kill US airmen at a base in Belgium, to release the poison ricin in Britain, and to bomb the US embassy in Paris.
"It is not humanly possible to stop everything," however, says Daniel Benjamin, a former National Security Council counterterrorism chief and author of "The Age of Sacred Terror." "We can beat them 20 times, but if they beat us once, it makes it look like they are winning."