RIYADH, Saudi Arabia -- During the 1980s and 90s, the historic alliance between the wealthy monarchy of Saudi Arabia and the country's powerful clerics emerged as the major financier of international jihad, channeling tens of millions of dollars to Muslim fighters in Afghanistan, Bosnia and elsewhere. Among the project's major patrons was Prince Salman bin Abdul-Aziz Al Saud Salman, who last month became Saudi Arabia's king.
Some of those fighters later formed al-Qaida, which declared war on the United States and later mounted major attacks inside Saudi Arabia as well.
In the past decade, according to officials of both the George W. Bush and Barack Obama administrations, the Saudi government has become a valuable partner against terrorism, battling al-Qaida at home and last year joining the U.S.-led coalition against the extremists of the Islamic State.
Yet Saudi Arabia continues to be haunted by what some suspect was a tacit alliance with al-Qaida in the years before the Sept. 11, 2001, terrorist attacks. Those suspicions burst out in the open again this week with the disclosure of a prison deposition of a former al-Qaida operative, Zacarias Moussaoui, who claimed that more than a dozen prominent Saudi figures were donors to the terror group and that a Saudi diplomat in Washington discussed with him a plot to shoot down Air Force One.
Saudi officials have staunchly denied those claims, noting that Moussaoui was a convicted terrorist with a history of mental troubles and little to lose by spreading lies about Saudi officials. On Wednesday, experts on the kingdom also expressed strong doubts about Moussaoui's claims.
By 1994, when Osama bin Laden was stripped of his Saudi citizenship and banned from the kingdom, the al-Qaida founder was "writing nonstop against the Saudi regime with the idea of toppling it," said Bernard Haykel, professor of Near Eastern studies at Princeton. "That the Saudis would knowingly support a movement that sought to destroy them makes no sense to me."
But Moussaoui's sensational allegations have drawn attention in part because far more credible figures, including some members of the national 9/11 Commission, believe the Saudi role in the attacks has never been adequately examined. More broadly, the episode has drawn new attention to Saudi Arabia's longtime policy of using its oil wealth to try to shape foreign battlefields, currently by backing militants in Syria and Libya, and the reactionary religious ideology that underlies its society.
Throughout the 1980s, Saudi Arabia and the U.S. were partners in bankrolling the mujahedeen, hailed as freedom fighters by President Ronald Reagan, who were battling the Soviet military in Afghanistan.
Some of those fighters coalesced under the leadership of bin Laden in 1988 to form al-Qaida, which soon put the Saudi state on its list of enemies along with the United States. While private Saudi support for bin Laden's organization continued to flow, experts who study the kingdom said they doubted it would have come from top officials like those named by Moussaoui, at least after 1994.
The investigation of 9/11, in which 15 of the 19 hijackers were Saudi, would likely have turned up such high-level support if it existed, said F. Gregory Gause III, a professor at the Bush School of Government and Public Service at Texas A&M University, who studies Saudi Arabia.
Among the donors Moussaoui said were in an al-Qaida database that he helped create were Prince Turki al-Faisal, then the head of Saudi intelligence, and Prince Bandar bin Sultan, the Saudi ambassador to Washington.
Both held high positions in the very government that al-Qaida was by the late 1990s openly seeking to destroy, he said.
Charles W. Freeman Jr., who served as U.S. ambassador to Saudi Arabia from 1988 to 1992, said he tried to warn Saudi officials of the dangers of religious extremism, at first with little success. But that changed during the '90s, he said.
"By the time Zacarias Moussaoui claims he was listing these people as supporters, they were anything but," Freeman said.
A third prominent name Moussaoui listed was Prince Alwaleed bin Talal, a fabulously wealthy investor who whose television channels air racy music videos and who employs men and women side by side in his offices.
"I doubt he would be a natural supporter of al-Qaida," Gause said.
In an emailed response to questions, Alwaleed's office said that "the charges made by Mr. Moussaoui, a convicted criminal, are patently and absurdly false," adding that "Prince Alwaleed has never hesitated to condemn al-Qaida and its allies."
Turki now heads a research institute in Riyadh and travels often to the United States where he meets with officials. Bandar was recently relieved of his post as the head of Saudi Arabia's National Security Council. Turki did not respond to requests for comment, and Bandar could not be reached for comment.
Saudi officials pointed to assertions of Moussaoui's defense lawyers in 2002 that he "suffers from a psychotic mental disease" that included "grandiose delusions." Despite those claims, however, the judge at his 2006 trial pronounced him competent and praised his intelligence before sentencing him to life in prison.
Moussaoui is a prolific writer of letters to judges, and it was his letter offering to testify in a long-running lawsuit of 9/11 survivors against Saudi Arabia that led to his deposition last October. Last November, two weeks after the deposition, he wrote a federal judge in Oklahoma accusing Turki of instructing a Saudi official to help the future 9/11 hijackers. He also claimed that Bandar's wife, Princess Haifa al-Faisal, "gave me money" and sent a large amount of money to the Saudi hijackers.
He offered no details except to say that he had met Turki in Norman, Oklahoma, in 2001. A search of news stories from that period turned up no references to a visit by the Saudi intelligence chief to Oklahoma that year.
Some specialists on Saudi Arabia noted that Moussaoui and some of the hijackers were students who could have received financial support that had nothing to do with the attack plans.
The ultimate turn in Saudi counterterrorism policy came after 2003, when al-Qaida mounted attacks inside the kingdom.
"I don't think Saudi Arabia really grasped the domestic threat that they posed until early in this century when there were explosions and they started killing people," Freeman said.
Since then, U.S. officials have praised the Saudi government for cracking down on militants inside the kingdom and for acting to stop terrorist financing by Saudi citizens. But the kingdom has continued to support militant groups other than al-Qaida and armed tribes that it sees as advancing its policies in Libya, Syria and elsewhere. And at home, the kingdom's traditional religious establishment promotes and enforces a strict interpretation of Islam.
Saudi ways are as alien to Americans as gender equality and sexual freedom in the U.S. are to many Saudis. Cultural difference have long fueled suspicions on both sides, despite close economic and security ties, said Thomas W. Lippman, author of two books on the kingdom. "At the ideological level, it's a relationship of mutual revulsion," he said.