The Council on American-Islamic Relations, a national Muslim civil rights group that has frequently drawn fire from conservatives, has regained its tax-exempt status. The Washington, D.C.-based CAIR and its related foundation were two of about 275,000 nonprofits that lost tax exempt status last year for not filing tax returns for three years in a row. Last month, the Internal Revenue Service sent a letter to the CAIR-Foundation Inc., saying the nonprofit had regained its tax-exempt status.