A student is behind bars after what police are calling a “serious assault” at Montgomery High School. A letter to parents says a student was injured in a fight that happened in a girls’ restroom on Tuesday afternoon. At about nine p.m., the Santa Rosa Police Department announced a 14-year-old girl had been arrested on suspicion of assault and robbery. Police say there’s no indication that a weapon was involved. This is the latest violent incident at Montgomery High School, where a student was stabbed to death during a fight in an art class last March.