Five Muslim-Americans who were fingerprinted, searched and held up to 6 1/2 hours by US border agents upon their return from a religious conference in Canada are suing the Department of Homeland Security. The suit filed Wednesday in US District Court in Brooklyn charges the government violated their constitutional rights to practice religion and against unlawful searches. Plaintiff Karema Atassi, 22, of Williamsville, was among at least three dozen Muslim-American men and women who were stopped at two western New York border crossings in December. They had been attending an annual "Reviving the Islamic Spirit" conference in Toronto. The suit was brought by the New York Civil Liberties Union, the American Civil Liberties Union and the Council on American-Islamic Relations.