Opponents of a Canadian immigration law that allows authorities to detain terror suspects indefinitely without trial were preparing to challenge it before Canada's Supreme Court, as the country reels from the recent arrests of an alleged homegrown terrorist ring. Opponents say the law violates the country's Charter of Rights and Freedoms in part because it allows for lengthy detentions based on secret evidence and without the right to appeal. Five Arab Muslim men, held for years under "security certificates" that deem them a threat to national security, face deportation on suspicion of terrorist activities. The men claim they are innocent and face torture if returned to their native Algeria, Morocco, Syria and Egypt. Human rights and immigration lawyers will argue Tuesday before Canada's highest court, challenging the constitutionality, conditions of detention and undisclosed evidence against the men under the provision of Canada's Immigration Act.