U.S. citizen or not, I would rather a guilty man go free than an innocent man be imprisoned. The chance that a terrorist could be among them is a chance we have to take. We don't detain people indefinitely on suspicion with no evidence. Of course war time is different, but if we're at war (which we aren't) then they are POWs and subject to Geneva protections. Otherwise they should be innocent until proven guilty - you know, one of the basic human rights we stand for. We cannot let terrorists terrorize us into becoming a country of fascists willing to disregard basic human rights out of fear.