A 12-year-old girl was arrested after a gun in her backpack accidentally went off at Salvador B. Castro Middle School in Los Angeles, injuring five people. The most seriously hurt was a 15-year-old boy who was shot in the head, but doctors said the bullet didn’t hit anything vital or life-threatening. A student at the school told AP that the crying girl told him, “I didn’t mean to. I had the gun in my backpack and I didn’t know it was loaded and my backpack fell and the gun went off.” The girl was booked into Juvenile Hall last night on suspicion of negligently discharging a firearm on school grounds. Police haven’t said where she got the semi-automatic handgun or why she brought it to the school.