A Spanish investigating judge today said he had concluded a comprehensive, eight-year probe into Islamic extremist activity in Spain, and his report will likely lead to formal charges and trials for 15 suspected militants accused of helping to plan the Sept. 11, 2001, terrorist attacks in the United States, according to media reports here citing the unreleased document.

The judge, Baltasar Garzon, did not make his conclusions public, but the Spanish news reports, citing court sources, said 14 people now in custody and one man free on bail face terrorism charges for the attacks on the World Trade Center and the Pentagon. Under Spain's legal system, judges have wide latitude to conduct lengthy investigations. The results form the basis of prosecutions, indictments and trials.

Among those named in the report is Imad Eddin Barakat Yarkas, also known as Abu Dahdah, the alleged leader of Osama bin Laden's al Qaeda network in Spain. The news reports said he would be charged with 3,000 counts of murder for the Sept. 11 attacks.

Spanish investigators have said that a principal suspect charged in the March train bombings in Madrid, a Moroccan immigrant named Jamal Zougam, was a follower of Yarkas. Yarkas has been jailed since November 2001.

Another judge, Juan del Olmo, is investigating the train bombings.

Of the 15 people reportedly named by Garzon, only one is free on bail: Taysir Alouni, who was born in Syria, lives in southern Spain and works for the pan-Arabic television network al-Jazeera. Alouni interviewed bin Laden shortly after the Sept. 11 attacks, and Spanish news reports Tuesday said he was accused of providing money and information to al Qaeda.

Court sources told news agencies that trials for the 15 could begin in about a year.

The only other prosecutions from the Sept. 11 attacks have been in Hamburg, where the conviction of one suspect was overturned on appeal and another defendant was acquitted, and the current federal case in Northern Virginia against Zacarias Moussaoui, a French citizen who is charged with conspiracy. He was arrested a month before the attacks on an unrelated immigration charge.

Garzon began his probe into Islamic terrorist groups in Spain in 1996. The investigation intensified after the Sept. 11 attacks and led last year to several indictments, including charges brought against bin Laden. Garzon and investigators have said Spain has jurisdiction to bring charges for the Sept. 11 attacks because much of the planning is believed to have taken place here, as well as in Germany.

In March and April, Spanish investigators, who spoke on condition of anonymity, said the leader of the Sept. 11 hijack team, Mohamed Atta, was known to have visited Spain twice in the months before the attacks, in January and July 2001. On July 7, 2001, with the attack planning in its final stages, Atta flew from Miami to Madrid on an American Airlines flight using an Egyptian passport and a U.S. visa, a Spanish investigator said. Atta traveled to Salou, a beach resort in the Catalan region, and stayed one night, July 17, at the small Montsant Hotel, paying $30 with a credit card for a room.

Atta also traveled in July to Tarragona, where much of the final planning for the Sept. 11 attacks is believed to have taken place. Investigators have said he rented a car and are trying to trace his credit card records to determine his movements. Atta left Spain for Miami on July 19, an investigator said.

Yarkas had drawn the attention of Spanish investigators since at least 1996. He has been described as the leader of an al Qaeda "sleeper cell" operating in Spain and is said to have maintained close links with key operatives in Europe. Yarkas is also believed to have traveled to Pakistan and Afghanistan.

The Spanish radio station Cadena Ser on Tuesday quoted Garzon's report as saying it was "evidently clear" that Yarkas "had been in relations with some of the perpetrators of the Sept. 11 massacre" and that he had given "ideological preparation and financial and logistical support to diverse members of the organization" that moved from Spain to carry out missions in Afghanistan, Chechnya, Bosnia and Indonesia.

Investigators in March and April said that Yarkas appeared to support his network largely by using credit cards stolen from the mail.

Much of Garzon's information came from a Syrian member of al Qaeda, Khayata Kattan, who was arrested this year in Jordan and extradited to Spain. Kattan made two appearances before Garzon, on Feb. 4 and 5, and detailed in a taped declaration how he spent time in a Bosnian training camp in 1995 before coming to Spain as a money-carrier for Yarkas, taking cash to militants in Chechnya and Kenya.

Imad Eddin Barakat Yarkas, the alleged al Qaeda leader in Spain, may face murder charges for 9/11.