RALEIGH, N.C. — Nine years of scrutiny have made some American Muslims wary of the federal government, and that has the U.S. Census bureau working to make sure its crucial survey doesn’t become a casualty of fear.

Muslims are not the only group the agency has identified as needing special attention, but they may be among the likeliest to shun the mail-in questionnaires.

America’s Muslim population includes large numbers of recent immigrants, and community leaders say nearly a decade of bearing the brunt of the country’s post Sept. 11 terrorism fears have taken their toll.

“You still have people in a kind of paranoid state of mind,” said Khalilah Sabra, director of the Muslim American Society’s Freedom Foundation in North Carolina.

That might be particularly true in the Raleigh-Durham area, she said, where seven local Muslim men were arrested in July and charged with plotting to travel overseas to carry out acts of terrorism.

The census is prohibited from sharing information that could identify individuals, including with other federal agencies or law enforcement. Census workers also take an oath, swearing for life to protect the confidentiality of data, with a possible five years in prison for breaching that trust.

Technically, no Muslims will be counted at all. Also absent from the count will be Christians, Jews, Zoroastrians and religious believers and unbelievers of all kinds, because religion is not a category tracked by the census.