CAMP HAMAC, Dipolog City: An old buried rifle grenade discovered by Grade 7 student Clark Simbajon, 15, while he was collecting junk in Barangay Ganase in Liloy, Zamboanga del Norte, accidentally exploded last Friday, seriously injuring Grade 6 pupil Michael Baunillo, 12, and his teacher Desiderio Acain, 54. Provincial Police Director Col. Michael Macapagal said the grenade was found in the abandoned house of retired Army soldier Ferdinand Fabian. Police said the rusty grenade was brought home by Simbajon, whose younger brother Jemar, 12, later brought it to school. Jemar and his classmates Rhanie Erro,12, and Rocky Arnaiz, 12, toyed with the rifle grenade in front of their school building where tutor Acain was standing when it exploded. Teacher and student were seriously injured and given a 50-50 chance to survive.