In Los Angeles, police arrested a 12-year-old girl Thursday, charging her with negligent discharge of a firearm, after a shooting at the Sal Castro Middle School left four people injured. Police now say the girl unintentionally triggered a semiautomatic handgun brought into a classroom. Among those hurt was a 15-year-old boy who was shot in the head. Officials said he was expected to fully recover. The U.S. Gun Violence Archive reports this was the 166th accidental shooting so far this year—with over 2,000 such incidents last year alone.