The anxiety and anger have been building all year. In March, a national coalition of Islamic organizations warned that it would cease cooperating with the F.B.I. unless the agency stopped infiltrating mosques and using "agents provocateurs to trap unsuspecting Muslim youth."
In September, a cleric in Bay Ridge, Brooklyn, sued the government, claiming that the F.B.I. had threatened to scuttle his application for a green card unless he agreed to spy on relatives overseas --- echoing similar claims made in recent court cases in California, Florida and Massachusetts.