Two Hilo High School students have been suspended for six days. The two 16-year-old boys were suspected setting off a small explosive device at the school on Thursday.  Police arrested the boys on suspicion of terroristic threatening. The school went on lockdown after the explosion.  Department of Education Spokeswoman Donalyn Dela Cruz says further DOE disciplinary action will depend on the police investigation. Because the teens are minors the matter will probably be handled by the Family Court behind closed doors.