Police arrested a 12-year-old girl Thursday after a morning shooting at Los Angeles middle school left five people injured, including two with significant gunshot wounds, officers said.

The young girl was not identified because she is juvenile. She is facing charges for negligent discharge of a firearm. A 15-year-old boy was shot in the head but doctors stabilized him, officers said. A 15-year old a girl was shot in wrist and was being hospitalized.

Two other students, ages 11 and 12, suffered graze wounds, and a 30-year old woman suffered a minor injury after the shooting, officers said.

The shooting was reported at 8:55 a.m. Police didn’t say what led to the shooting, and only a little information was released about the girl who was detained. City school police chief Steven Zipperman said she was 12 and that she and witnesses were being interviewed.

What led to the shooting is still under investigation.

A boy who was shot in the pupil is “extremely lucky” doctors said, and they expect him to recover. The girl who was shot in the wrist was also still being hospitalized. The other two students were grazed, treated and released, Strumwasser said.