Two Egyptian college students already accused of illegally carrying explosive materials now face more charges. The US Attorney's Office in Tampa says a grand jury issued a new indictment Wednesday charging former University of South Florida students Ahmed Abdellatif Sherif Mohamed and Youssef Samir Megahed with an additional charge of possessing a destructive device. Mohamed also faces new charges of providing material support to terrorists and possessing a pistol and a rifle in violation of visa guidelines. The FBI says he made a video demonstrating how to convert a remote-control toy into a detonator for a bomb. The two were arrested after deputies in South Carolina last August discovered what they described as bomb-making materials in their trunk during a traffic stop. Lawyers for the men have said the materials were homemade fireworks.