My bad. Had heard they were both here on legal greencards as were the parents before they returned to Russia. How did he become a citizen? Although, even as a citizen he could be subjected to military law/Geneva Convention rules - if it's proven he was part of an international terror group. He also would still be subject to civilian law - both Fed and State - afterwards. The military justice system does follow procedural laws of due process but they can often be different in structure.