When the Saudi police burst into a classroom at the Islamic University of Medina during final exams two years ago and whisked away an American exchange student named Ahmed Omar Abu Ali, his imprisonment swiftly reverberated among Muslims in this Washington suburb.
Mr. Abu Ali was never charged, and he spent 20 months in a Saudi prison where his family says he was whipped, tortured and starved. This week, he was finally returned to Virginia - only to face an accusation by American prosecutors that he had plotted with members of Al Qaeda to assassinate President Bush.
The charge has outraged members of Northern Virginia's growing Muslim population and escalated a conflict with federal law enforcement authorities over terrorism investigations into religious leaders, mosques, businesses and private Islamic schools in the region.
"Our whole community is under siege," said Imam Johari Abdul-Malik, a spokesman for the Dar Al-Hijrah mosque in Falls Church, where Mr. Abu Ali and his family worshiped. "They don't see this as a case of criminality. They see it as a civil rights case. As a frontal attack on their community."
In many ways, Mr. Abu Ali embodies the conflicting images of Muslims in Northern Virginia that have emerged from the many local prosecutions. And his case underscores how religious institutions that some local Muslims view as mainstream are coming under scrutiny by investigators determined to prevent terrorist attacks.
Mr. Abu Ali's parents and friends have portrayed him as a pious, studious and gentle man who went to Saudi Arabia to learn more about his religion. He was the valedictorian at his Islamic high school in Northern Virginia, a camp counselor for his mosque, a well-known youth leader who donated his free time to helping the elderly and tutoring children, they say.
But government officials depict a darker side to Mr. Abu Ali and the institutions that were central to his youth. His Saudi-subsidized high school, they contend, was a potential breeding ground for an extreme, dogmatic form of Islam. Two of the Sept. 11 hijackers briefly attended his mosque. And several lecturers at an Islamic college that he attended in Fairfax, Va., which also had ties to the Saudi government, lost their visas last year after critics accused them of preaching intolerance.
Mr. Abu Ali also had clear ties to several defendants in a case involving 11 Northern Virginia Muslims accused of plotting to wage war against American forces and allied nations overseas. Prosecutors say he provided an AK-47, by all indications legally, to one of the defendants. And he may have occasionally played paintball with the group - an activity that served as paramilitary training, prosecutors say.
Which portrayal of Mr. Abu Ali is closer to the truth may not become clear until he is tried, and perhaps not even then. But until then, his case and the others preceding it have galvanized Muslims in the region.
"The feeling I get here on a daily basis must be what it was like to be a member of Martin Luther King Jr.'s church following the case of Rosa Parks," said Imam Abdul-Malik. "People always ask, 'What is the latest from the courthouse?' "
There have been many courthouses to visit and many court dockets to monitor, as Muslim suspects in the Washington area have been the targets of some of the federal government's most contentious and far-reaching terrorism investigations since the Sept. 11 attacks.
In what prosecutors call the "Virginia Jihad case," nine people were convicted last year on charges including conspiring to wage war against American allies and illegal possession of weapons. Many Muslims refer to the trial derisively as "the paintball case" because they say the local men did little more than play games in rural fields.
That case was followed by the indictment of Ali al-Timimi, a charismatic leader known for his fiery sermons at a storefront mosque in Falls Church. Prosecutors say Mr. Timimi, who is awaiting trial in May on terrorism-related charges, urged his followers, including some of the men in the Virginia Jihad case, to wage holy war against the United States.
In another case, Abdurahman Alamoudi, a prominent Arab-American from Falls Church, pleaded guilty last year to charges of laundering money from Libya and taking part in a foiled plot by President Muammar el-Qaddafi of Libya to assassinate a Saudi prince.
And Mr. Alamoudi, in turn, had financial links to a network of Islamic charities, businesses and educational institutions in Northern Virginia known as the Saar group, which for years has been the target of a federal investigation into accusations of terrorist financing and illicit connections to Saudi financiers.
Many of the defendants in those cases not only lived in Northern Virginia, but also attended Dar Al-Hijrah, one of the largest and most politically active mosques in the region. Members of the mosque have held dinners to raise money for some of those defendants, organized carpools to visit them in jail and held vigils outside courthouses.
For all those reasons, the mosque has come under closer scrutiny by prosecutors who say its brand of Islam may be encouraging sympathy for groups like Al Qaeda.
But experts say the mosque has encouraged its members to participate in American society and politics. And though its leaders adhere to Wahabism, the strict sect of Islam embraced by Osama bin Laden and most other Saudis, it has also called on its members to shun violence.
"They have lots of conservative material there," said M. A. Muqtedar Khan, director of international studies at Adrian College in Ohio, who attended Dar Al-Hijrah from 1995 to 2000. "Does that translate into their being instruments for recruitment for Al Qaeda? I don't think so."
Mr. Abu Ali was born in Houston, the first of five children of a Jordanian couple. When he was a small child, his family moved to the Washington area, where his father works as a computer programmer at the Saudi Embassy and leads morning prayers there.
After studying engineering at the University of Maryland for a year, Mr. Abu Ali decided to go to Saudi Arabia in 2000 to study - against the wishes of his parents, his family said.
"He said, 'I want to understand my religion,' " recounted his mother, Faten Abu Ali. "He wanted to go to the place of the birth of the prophet."
Mr. Abu Ali was in Saudi Arabia at the time of the Sept. 11 attacks, and his mother remembers him expressing dismay at the carnage. "He was shocked, frustrated," she recalled. "He said, 'This is not Islam.' "
But prosecutors charge that it was there, at the Islamic University of Medina, that Mr. Abu Ali's views became radicalized. A friend from the university introduced him to a Qaeda associate - whom Saudi officials would later link to the Riyadh bombing in May 2003 - and Mr. Abu Ali is accused of joining a clandestine Qaeda cell in late 2002 or 2003.
Mr. Abu Ali's intent, prosecutors charged, was not to be a mere foot soldier in the Islamic struggle but a terrorist leader like Mohammed Atta or Khalid Shaikh Mohammed, two main figures in the Sept. 11 attacks. Indeed, prosecutors charged that his mission reached the highest levels, as he discussed the possibility of getting close enough to President Bush to shoot him or detonate a car bomb near him.
But whatever plan may have been hatched appears to never have progressed beyond discussion, American officials acknowledged. In fact, the Qaeda associate who they say discussed the plot with Mr. Abu Ali was killed by Saudi authorities in a shootout a few months after the men's alleged discussions.
Mr. Abu Ali's father said he did not hear from his son for two months after the Saudi police imprisoned him in 2003. His first words to his family were, "I have been on a long trip in a wild jungle," a message his father interpreted to mean he had been tortured.
The Saudi and American governments have vehemently denied that he was tortured.
The family filed a suit in Washington to force his release from Saudi custody, and after a federal judge expressed support for many of the family's contentions, he was returned to the United States to face the assassination charges. Many Muslims now see those charges as an effort to deflect public attention from the family's accusations of abuse.
"This is revenge," said Shaker Elsayed, a friend of the Abu Ali family.
Officials at the Federal Bureau of Investigation are careful to distinguish between the "extremists" who have caught their attention and the larger, law-abiding Muslim population, and they emphasize that they depend on information from Muslims to develop terrorism leads.
As a result, the F.B.I. has conducted outreach programs and community meetings in heavily populated Muslim areas like Washington and Detroit to foster relations and ramp down resentments caused by wide-scale interviews of Middle Eastern men in the United States and other controversial tactics.
"What I try to do in these outreach efforts with the Muslim community," said Michael Mason, an assistant director at the F.B.I. who heads the Washington field office, "is to let people know that they needn't be afraid of the F.B.I. and that we're operating in a legal, open manner."
Mr. Mason said he was so concerned over those relations that he called members of an Arab-American outreach council that the F.B.I. has relations with to let them know in advance last Monday night that Mr. Abu Ali was being returned to the United States.
Acknowledging concerns among Muslims about the young man's case, he said: "It's too early to tell whether this will hurt us or not, but I think we have good enough relations with Arab-American leaders that most are willing to take a wait-and-see attitude and see how the case plays out."