In late January, workmen in Chantilly erected a minaret on the roof of a new building, the first highly visible sign that it was to be a mosque. That night, vandals hurled rocks at its arched windows, shattering many. Empty beer cans and liquor bottles were scattered on the mosque’s grounds and roof.

The attackers left no written message, and police have not found them. But if their intent was to ostracize or frighten the worshippers, mostly of Pakistani origin, it didn’t work. Religious and political leaders across the region quickly issued statements of condemnation. A week later, at a regional interfaith meeting in Sterling, officials from a variety of congregations expressed their outrage and sympathy.

“We were a little surprised, because this is a conservative area. But the attack seems to have brought the community together in a positive way,” said Shahid Malik, an engineer and official of the mosque. “I think civic leaders here have gotten to know us. They see that we are helpful and hard-working and that we condemn terrorism. What happened was unfortunate, but it had a silver lining.”

To members of the mosque, the incident was an alarming echo of the persecution their sect, known as the Ahmadiyya Muslim Community, has faced for years in Pakistan. It also came at a time when some political and religious figures in the United States warn that the proliferation of Muslim immigrants and mosques represents a danger to American society.

In contrast, local groups took pains to reassure the Chantilly mosque members that they are a welcome part of the region’s rapid diversification. Once mostly white, the Dulles region is now a mosaic of international cultures and faiths, from Indian Sikhs to Vietnamese Buddhists.

Pam Broaddus, a member of New Life Methodist Church in Herndon, said the two groups developed a “very positive relationship” when the church was next door to an Ahmadi worship center. “They always let us park in their yard.”

Broaddus said that with change coming so fast to the area, “some neighbors may not have been happy that a mosque was going up, but everyone I know felt awful about what happened.”

Within the region’s Muslim community, condemning the vandalism held a different but equal significance. To most Americans, Ahmadis are indistinguishable from other Muslims, whether women shopping while wearing head scarves or men gathering to pray. But many foreign-born Muslims, especially Sunnis, believe Ahmadis are dangerous infidels because they believe in a modern-day messiah and do not accept Muhammad as the final prophet.

The Ahmadiyya movement was founded in the 1890s in Punjab, India — now part of Pakistan — by a spiritual leader named Mirza Ghulam Ahmad. Its followers obey the main tenets of Islam and revere the prophet Muhammad, but they also believe Ahmad was the messiah, a doctrine that many other Muslims see as blasphemy. The Ahmadis’ principal slogan is “love for all, hatred for none.”

In Pakistan, radical Sunni groups have repeatedly threatened Ahmadis, and the government has refused to acknowledge them as Muslims, thus opening the door to public hatred. In recent years, Ahmadi leaders have been harassed and killed. In 2010, nearly 100 people died when terrorists attacked two Ahmadi mosques in Lahore.

Among the roughly 20,000 Ahmadis living in the United States, many immigrated to escape harassment or have friends and relatives who have suffered back home. There are about 1,000 living in the Washington region, including a handful of non-Pakistanis.

“The language of hatred is used against us in many forms. The extremists do not want us to live a normal life,” said Usman Ghumman, a member of the Chantilly mosque. “It is different here in America, where other Muslims don’t have to worry about what the mullahs would say if they are close to us.”

Officials of the All-Dulles Area Muslim Society, where most worshippers are Sunnis, issued an especially strong statement against the vandalism at the mosque and led an effort to unite other faith communities in condemning it. The group said it was “deeply saddened” and expressed confidence that such “heinous acts” would not change America’s tradition as a “beacon for religious freedom.”

Twenty religious groups from the area joined in the statement, including Christians, Jews, Muslims and Sikhs.

“We are very concerned about what happened,” said the Rev. Clark Lobenstine, executive director of the Interfaith Conference of Metropolitan Washington, which represents 11 groups and published a letter on its Web site protesting the Chantilly attack. “For us, it is clearly an issue of religious freedom.”

Some members of his group were not previously familiar with the Ahmadiyya sect, Lobenstine said, but the vandalism was “clearly focused on that mosque” and it was important to “speak out in all situations where religious freedom is threatened.”

Rizwan Jaka, a board member at the All-Dulles Area Muslim Society, said that although sectarian disputes often consume and divide Muslims overseas, all who immigrate should adapt to U.S. laws and seek to present a moderate and non-threatening image of Islam.

“In America there is a beautiful diversity. Differences may exist, but in a multi-religious society, we must all get along,” Jaka said. “Freedom of religion is a main concept in Islam, and an attack on any faith community is an attack on all.”

Jaka compared the Ahmadis to Mormons — a prosperous but insular religious minority that believes in a modern prophet.

Local Ahmadi leaders, steeped in a history of victimization, remain sensitive about their image and vigilant against future attacks. Organized and determined, they have achieved both sanctuary and success in America. In 1994, they built a modern, spacious mosque in Silver Spring. But in 2007, plans to build a conference center near Frederick met with such strong local opposition that they abandoned it.

American Ahmadis are largely middle-class professionals, and they publicly promote values of patriotism, peace and public service. They are extremely traditional in their religious and family values. Ahmadi women work and go to college, but they do not shake hands with men, are segregated during worship and do not marry outside the sect.

“I am very passionate about Ahmadiyya. It is a wonderful guide for life,” said Labeeda Malik, 23, who studied marketing at George Mason University and said she often challenged other students to guess what kind of Muslim she is. “Sometimes they have heard bad things about us and they ask questions, but I like explaining our beliefs,” she said. “By the end of the discussion, they are usually more open.”

Last weekend, several hundred Ahmadis met at the Silver Spring mosque to discuss new security measures, including volunteer night patrols, to prevent attacks. The community is already holding fundraisers to complete the Chantilly mosque. The destruction on Jan. 30 caused about $60,000 in damage.

Some members said privately that several Sunni mosques were preaching against them, but Naseem Mahdi, a senior Ahmadi cleric, seemed unworried and said he had been warmly received in many Muslim and Christian communities.

“We have extremists in both countries,” said Mahdi. “But the vast majority of people here are moderate and peaceful. When I came to America, I thought I was entering semi-hostile territory. I have been proven wrong.”

In the neat townhouse community that adjoins the half-built mosque in Chantilly, homeowners are a mix of immigrants from Asia and the Middle East and native-born Americans. Last week, several residents expressed a mixture of sympathy over the vandalism and live-and-let-live indifference to the Ahmadis.

“Those people believe a little bit differently from what we believe, but there are no bad feelings,” said Cheman Waise, a day-care administrator and Sunni immigrant from Iraq. “In America, discrimination is illegal, and all people are treated the same under the Constitution. If they worship a different way, it is not a big issue.”

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