AIRO, Sept. 14 ・Saudi Arabia's track record in previous terrorism investigations has been one of keeping its distance from the United States. It is a distance that illustrates a challenge: how does Washington square Saudi Arabia, the loyal ally and vital oil supplier, with Saudi Arabia, the guardian of Islam, a power of the Arab world and birthplace of suspected terrorists?

In past cases when it has been called upon to investigate terrorism, Saudi Arabia seemed less concerned with finding the killers than with making sure it did not stir up radical opponents at home who might paint members of the royal dynasty as American lackeys.

Despite evidence suggesting that some of those who carried out the massive attack on the United States this week might have been Saudi citizens or at least linked to another former Saudi resident, Osama bin Laden, it remains to be seen to what extent the kingdom will aid the United States in taking on his shadowy movement. Some Saudi officials noted that names bandied about this week as armed and dangerous men and even suicide pilots turned out to be average Saudi citizens sitting quietly home in Jidda and Mecca, their flight training over.

While Saudi diplomats and other officials reached by telephone remained noncommittal and said there had been no formal American request for help, there were unusual expressions of support.

The Saudi chief justice, Sheik Saleh bin Muhammad al-Luhaidan, not normally the kind of figure to express public sympathy for the West's problems, condemned the attacks. He added his voice to that of senior royal figures, including King Fahd, Crown Prince Abdullah and Prince Bandar, the Saudi ambassador to Washington.

"We in the kingdom of Saudi Arabia are fully prepared to cooperate with you in every way that may help identify and pursue the perpetrators of this criminal incident," the official Saudi Press Agency quoted Prince Abdullah as telling President Bush in a telephone conversation this week.

Among Saudis there was a sense that the movement of Mr. bin Laden, if indeed it carried out this week's attacks, had moved beyond the pale.

"If in the past there were supporters or sympathizers or admiration, what happened in New York will turn it off," said Jamal Khashoggi, the managing editor of The Arab News in Jidda, who spent years covering Islamic movements. "He is dragging all of us into a conflict with the West that we don't want."

Once, Mr. bin Laden was a kind of icon for young children in Saudi Arabia and the Arab world who spent their free time collecting piasters to help him and other mujahadeen dedicating their lives to freeing Afghanistan from Soviet tyranny.

No one remembers Mr. bin Laden actually soliciting funds. His father, a billionaire contractor, left him a healthy inheritance. But during the battle for Afghanistan in the 1980's, richer patrons around the Persian Gulf were generous, adding their millions to funding from the governments of the United States ・then backing Islamic warriors against the Soviets ・and Saudi Arabia, among others.

That seemingly stopped when Mr. bin Laden's increasing radicalization in the 1990's finally prompted the Saudis to strip him of his passport in 1994. His criticism for the way the royals were running the country dried up any official support. His wealthy family disavowed him too.

Anyone found overtly supporting Mr. bin Laden would have risked having all assets in the kingdom seized. Yet the Saudi government finances various conservative religious organizations without much rigorous accounting of where the money goes.

The Saudi authorities, guardians of Islam's most holy shrines, have never been able entirely to smother the idea that Mr. bin Laden was engaged in a glorious and glamorous struggle. To this day, young Saudis and other Arabs find their way to Mr. bin Laden in Afghanistan, if not in very large numbers. The ruling family allows no domestic dissent, so radical Islam has always served as the outlet for those who would topple their government.

The arrival of hundreds of thousands of American troops in 1990 to expel Saddam Hussein and Iraq's forces from Kuwait galvanized recruitment. Fervent followers of Islam were horrified that infidel troops had been brought into the land of Mecca and Medina.

That animosity only deepened after the United States military established a permanent air force presence to patrol the skies over Iraq.

In 1995, after a terrorist bombing in Riyadh killed four Americans working in Saudi Arabia to train the National Guard, their killers made televised confessions in which they said they had never met Mr. bin Laden, nor did they work for him. But they made it clear that he was their inspiration.

In that case, investigators from the F.B.I. who had hoped to interview the suspects never got the chance. The men were beheaded.

After a bombing at the Al Khobar towers in Dhahran in June 1996, which killed 19 American servicemen, the F.B.I. was similarly thwarted. Its investigators were denied access to evidence like the getaway car, although after endless wrangling they were eventually allowed to watch from behind glass as Saudi investigators posed questions to the suspects.

Last June, after a federal grand jury indicted 13 Saudis and a Lebanese man for carrying out the Dhahran attack, Saudi Arabia expressed a lack of interest even though it held most of the men. Their own courts would handle the case, officials said.

"Maybe what has been published matters to the United States, but it does not concern us in any way at all," Prince Nayef, the interior minister, said in an interview then about the indictments.

At that time, many Saudis were grumbling about the kingdom's close ties to the United States. In the diwaniyyas, the nightly gatherings in Saudi homes where educated professionals discuss issues of the day, there was disgust over the lack of American support for the Palestinians in their uprising against Israel. "I consider the United States my enemy," said an educated Saudi at one such gathering.

Senior Saudi officials have signaled their displeasure in less harsh terms. Crown Prince Abdullah, who effectively runs the country because King Fahd is ill, spurned an invitation to visit Washington to meet with President Bush ・despite the close ties between the crown prince and Mr. Bush's father ・and the Saudi military chief of staff stayed away from this summer's usual joint talks.

The Saudi challenge posed by ties to Washington finds an echo in Egypt, which with its own violent Islamic insurgency has never wanted to be shown working closely with American intelligence on anything.

After the attacks, however, there has been a marked change in tone. Ordinary Egyptians have approached Americans on the street to tell them how profoundly ashamed and horrified they are by the attack.