The Maryland teen arrested last week for bringing a handgun to school was found to also have an AR-15 style rifle, ammo, grenades, a ballistic vest, and a list of grievances against his classmates at his home, investigators said Tuesday. Alwin Chen, 18, of Clarksburg High School carried a loaded handgun and knife on school grounds, and was charged with “possession of a handgun, possession of a firearm by a person under 21 years old and possession of a firearm on school property” after a school resource officer received information that Chen may have had a weapon. When confronted last Thursday, he was arrested without incident. Chen had also allegedly brought a firearm to school before. His defense claims he has no history of mental health, is an honor-roll student, and the additional weapons were legally obtained and were not stored in his bedroom.