MADRID, Spain — The most sweeping criminal indictment to arise thus far from the Sept. 11 attacks reflects a quiet but dramatic change in understanding by investigators here and across Europe of the terrorist organization known as al-Qaida, and the international Islamic radical-terrorist network of which, they now agree, it is merely a part.

As laid out in the indictment, the defendants' alleged activities — from arranging travel and providing introductions to procuring false documents and, especially, moving money — provide the first detailed look at one of al-Qaida's most potent weapons: the ability to call on networks of sympathizers whose collective numbers are far greater than al-Qaida's few hundred card-carrying members.

Not one of the dozen key defendants named here last month as members or supporters of an alleged Madrid-based cell accused of working for al-Qaida and helping advance the Sept. 11 plot is a native of Spain, or even nearby Muslim North Africa.

Instead, all migrated to Spain from the Middle Eastern nation of Syria, where — according to the Spanish indictment — most became affiliated with an ultramilitant Islamic group called the Syrian Muslim Brotherhood.

Virtually from the moment of the Sept. 11 attacks, investigators in Europe and the United States were perplexed by what appeared to be a Syrian connection to the hijackings, both here and in Hamburg, Germany, whose university campuses produced three of the four Sept. 11 pilots and several accused or convicted accomplices.

At first, some questioned whether the Syrian government had perhaps known of the plot, or even whether Syrian intelligence had somehow been involved. Neither now appears to be true, investigators say, citing Syria's limited but useful cooperation with Western intelligence agencies attempting to unravel the connection between Sept. 11, al-Qaida and the Muslim Brotherhood.

One senior German intelligence official described the Muslim Brotherhood as "one part of the intelligence network of the mujahedeen." The Brothers, the official said, are not an extension of al-Qaida but affiliated with it in the same way as Indonesia's Jemaah Islamiyah, which reportedly financed last year's Bali nightclub bombings with $30,000 provided by al-Qaida, or a Salafist group in Morocco that allegedly used $50,000 in al-Qaida money to pay for five suicide bombings in Casablanca earlier this year.

When al-Qaida first appeared on the terrorist scene in the early 1990s, the Muslim Brotherhood was already well-established. It was 70 years ago last year that the Syrian Brotherhood, an offshoot of the even older Egyptian Muslim Brotherhood, first dedicated itself to the overthrow of Syria's secular government.

In 1982, the Syrian army struck in an attempt to wipe out the organization, killing 5,000 to 10,000 Muslim Brothers in the Syrian city of Hama.

The Brothers who survived fled to neighboring Jordan and Saudi Arabia. From there, many went on to new lives in Germany, Italy, Belgium and especially Spain, where they obtained asylum or citizenship, married local women willing to convert to Islam, started families and went into business.

Some of the displaced Syrians did quite well. But rich or poor, many apparently retained their radical orientation into middle age. No longer young enough to fight in the jihad, but experienced in the mechanics of clandestine organizations, the Syrian Brothers were available to help al-Qaida with financing, the movement of arms and the recruiting of young Muslim fighters.

Before Sept. 11, 2001, the man now at the center of the Spanish case might have seemed a classic immigrant success story: Muhammed Galeb Kalaje Zouaydi, after fleeing his homeland under hazy circumstances, made one fortune selling kitchen appliances in Saudi Arabia and another developing low-income apartment blocks in Madrid.

But to Baltasar Garzon, the Spanish magistrate who issued the 690-page indictment last month, Zouaydi was much more than a flourishing entrepreneur. Garzon accuses Zouaydi of having distributed some $800,000 on behalf of al-Qaida by using his Spanish development company as cover, while keeping a second set of books to camouflage the transactions as legitimate expenses.

Zouaydi's lawyer, Maria Angeles Ruiz Martinez, said her client had emphatically denied the charges at a postindictment hearing that was closed to the media. So had each of the other 13 defendants present, she said. The remainder of the 35 men named in the indictment are fugitives or citizens of other countries whose extradition Garzon has requested.

Ruiz Martinez acknowledged in a recent interview that her client had joined the Muslim Brotherhood as a young man — not out of ideological conviction, she said, but only to help him obtain asylum in Jordan. The same, she said, was true for many of the other Syrian defendants.

Since arriving in Spain in 1998, according to Ruiz Martinez, Zouaydi donated tens of thousands of dollars — not hundreds of thousands, as Garzon alleges — to Islamic charities and individuals connected to Muslim fundamentalist organizations.

The money had come from Zouaydi's own pocket as a zakat, an Islamic tithe he made as gratitude for his worldly success, and had never been intended to support terrorism, the lawyer said. Asked about the discrepancy between her client's admitted transactions and the $800,000 cited by Garzon, Ruiz Martinez said the police had misinterpreted Zouaydi's ledger entries and in turn had misled the judge.

A second Syrian under indictment is Zouaydi's business partner in Spain, Ghasoub al-Abrash Ghalyoun, who during a 1997 visit to the United States videotaped a succession of American landmarks, including the Golden Gate Bridge, Sears Tower, the Brooklyn Bridge and the World Trade Center, the main target of the Sept. 11 hijackers.

Ghasoub claimed after his arrest last year that he had made the videotapes, which reportedly include views of the World Trade Center's twin towers from many angles, at the request of a Spanish architect who later testified that he didn't know what Ghasoub was talking about.

The U.S. Justice Department has alleged in court documents that Zouaydi funneled more than $200,000 to a single organization, the European office of the Bridgeview, Ill.-based Global Relief Foundation. The foundation's lawyers have denied accusations by the Bush administration that it diverted some of the contributions it received to terrorist organizations.

Ruiz Martinez confirmed that donations were made to Global Relief but said they had totaled only $36,000 and that the money Zouaydi used had not come from al-Qaida. She said she could shed no light on a report in two Spanish newspapers last year that some of the money Zouaydi gave Global Relief was used to buy arms from the Kosovo Liberation Army that were shipped to al-Qaida fighters in Afghanistan.

Sharing the center spotlight with Zouaydi is Syrian native Imad Eddin Barakat Yarkas, allegedly al-Qaida's chief contact among the Muslim Brothers in Spain, who in the mid-1990s reconstituted themselves at a local fundamentalist mosque as "The Soldiers of Allah."

Yarkas arrived in Spain in 1986 from Jordan, where he had initially fled after the Hama massacre. He married a Spanish woman and set himself up in Madrid as a small-time importer and wholesaler.

"I work in everything," Yarkas told Garzon after his arrest in November 2001, "clothes, cars, honey, rugs whatever comes around." Spanish prosecutors say Yarkas' business, like Zouaydi's, later became part of the support network for al-Qaida.

Yarkas' lawyer, Jacobo Teijelo, said his client had denied at the closed hearing any affinity for al-Qaida or terrorism, telling Garzon that while he supported Muslim fighters in Bosnia and Chechnya, the Sept. 11 attacks had been "a barbaric act" not sanctioned by Islam or the Koran.

Teijelo acknowledged, however, that Yarkas had given some $35,000 to Tayssir Alouni, a prominent correspondent for the Arab satellite news channel Al Jazeera who is accused in the indictment of carrying the money to Afghanistan while serving as a courier for al-Qaida.

Teijelo maintains that the payments to the Syrian-born Alouni had come from Yarkas' own funds and had been intended for widows in Syria.

Alouni, whose several visits to Afghanistan during 2000 were recorded by Spanish police, reportedly has acknowledged to Garzon that he did carry thousands of dollars from Yarkas to Afghanistan, and also to Turkey and Chechnya, but denies the money was intended to support al-Qaida or terrorism.

Al Jazeera and a Syrian journalists group in Spain have protested that the charges against Alouni, who covered the post-Sept. 11 fighting in Afghanistan and the war in Iraq, represent an effort to intimidate Al Jazeera and to punish it for its reporting, which some see as having an anti-Western bias.

Garzon's indictment says, however, that the charges "are supported by events that have nothing to do with (Alouni's) current profession as a journalist" and are based on events that occurred while Alouni worked as a translator for the Spanish news agency EFE before joining Al Jazeera.

The bulk of the information in the indictment was compiled before Sept. 11, 2001, by investigators from the Spanish National Police, the DGP, who began watching and wiretapping Yarkas some six years ago. As the investigation progressed, they began picking up intelligence on Zouaydi, Alouni and their associates.

Although at least two individuals close to the Sept. 11 hijackers in Hamburg subsequently fell into the DGP's net, the agency, like its counterparts the BKA in Germany and the FBI in the United States, was unable to fully assemble the puzzle until after Sept. 11.

One of the larger puzzle pieces is Mamoun Darkazanli, a Syrian-born businessman and alleged Muslim Brother who for the past 20 years has lived in Hamburg and who appears more often in the indictment than anyone except Yarkas or Zouaydi.

"According to comments made within Islamic circles," a DGP report states of Darkazanli, "he's been acting Sheik (leader) for more than 16 years, and they say he's one of the best."

A two-year investigation of Darkazanli in Germany has found extensive financial dealings with known and suspected al-Qaida operatives. Darkazanli has admitted that he knew the lead Sept. 11 hijacker, Mohamed Atta, during Atta's university days in Hamburg.

The Spanish indictment adds a new dimension to Darkazanli's activities across Europe, showing 30 calls to Tayssir Alouni's home or office from Darkazanli's Hamburg telephone number between August 1998 and August 2000.

On at least four occasions during the same period, Darkazanli traveled to Spain to visit Zouaydi, whom he had met previously in Saudi Arabia, and Yarkas, with whose family he had lived in Jordan. On one of those trips, Alouni accompanied Darkazanli to Madrid from the Spanish city of Granada.

Police and prosecutors here and in Germany do not know the purpose of Darkazanli's trips to Spain. But Garzon describes Darkazanli, whose extradition from Germany he has formally requested, as Osama bin Laden's "financier in Europe," and a crucial link between Spain and Sept. 11.

Garzon alleges that Zouaydi channeled some $20,000 to Darkazanli, either directly or through a close associate, a Hamburg taxi driver named Abdul Fatah Zammar — another Syrian native who is Alouni's brother-in-law and a cousin of Mohammed Haydar Zammar, the Hamburg auto mechanic who reportedly has admitted helping recruit the Sept. 11 hijackers on behalf of al-Qaida.

In a deposition taken last year by Ruiz Martinez, Darkazanli maintained that he and Zammar received only $9,000 from Zouaydi, intended for the purchase of a used car in Hamburg that would then be shipped to Zouaydi in Spain.

"For several days," Zouaydi recalled during an interrogation by Garzon, Darkazanli "looked to see if he could find an appropriate car for us." But such a car hadn't been found, Zouaydi said, and Darkazanli had returned the $9,000.

Records of Abdul Fatah Zammar's Hamburg account show, however, that while the money was received on May 25, 1999, the same amount was wired back to Zouaydi on July 22 — almost two months after it was sent, not "several days," raising questions about how the money had been used.

German investigators have expressed skepticism that a millionaire like Zouaydi would have needed to hire anyone to find him a $9,000 used car.

As an investigative magistrate, Garzon performs a function that is unknown to American jurisprudence but is probably closest to that of a grand jury. For the past two years, he has ordered the arrest of suspects and questioned witnesses in the case, a process that culminated on Sept. 17 with the indictment.

It will now be up to prosecutors to try that case before another court, a process that some of the lawyers involved predict will not begin for a year and could take another year to reach a conclusion.

Although belonging to or supporting a foreign terrorist organization is illegal in Spain, Garzon's indictment turns on the argument that Sept. 11 was partly rooted in Spanish soil. One fact in support of that argument is a visit to Spain, two months before Sept. 11, by Atta, who is believed to have piloted the first plane to strike the World Trade Center.

A post-Sept. 11 investigation found hotel employees on Spain's Tarragona coast who recalled seeing Atta with Ramzi Binalshibh, a sometime Hamburg student and full-time al-Qaida organizer who six days before the hijackings fled Hamburg for Spain and, later, Pakistan.

In an interview with Al Jazeera before his capture in Karachi, Pakistan, on the first anniversary of Sept. 11, Binalshibh boasted that he had been the Hamburg coordinator of the hijacking plot. The purpose of the Tarragona meeting, he said, had been to give Atta the final authority to choose the date and targets of the attacks.

Investigators here admit that they do not know who else attended the meeting, which occurred in 2001 between July 10 and 13. But they know from wiretaps on Yarkas' telephone that Darkazanli was in Granada with Yarkas and Alouni at the same time.

Garzon maintains that Yarkas and the Spanish al-Qaida cell contributed to the hijackings, in part, by helping arrange the meeting.

Asked whether Binalshibh, who has been extensively interrogated by American intelligence agents, had provided information linking Yarkas or Darkazanli with the Tarragona conclave, a senior German intelligence official shook his head and replied, "Nothing."

Another significant item, in Garzon's view, is a telephone conversation Yarkas had two weeks before Sept. 11.

While police tape recorders turned, Yarkas' caller reported from London that "they" had "entered the field of the aviation" and "have beheaded the bird."

According to the caller, "they" would start to "move" within a month. Interpreting "bird" as a reference to the American eagle, Garzon concluded that the caller was alerting Yarkas to the impending Sept. 11 attack.

The identity of the caller, who identified himself during the conversation only as "Shakur," remains a mystery. During a lengthy interrogation by Garzon, Yarkas refused to name the man.

Yarkas knows the answer, but he is not talking.

"If in the current state of events I identify a friend," Yarkas told the newspaper El Mundo last year, "he would be dragged by his arms into the same unfortunate destiny as mine. Surely they would accuse him just as unfairly as me."

Contributing: Drew Crosby.