SAN PEDRO, Calif. (KABC) -- A San Pedro mother claims the Los Angeles school police used excessive force against her son without probable cause.Andres Munoz, 11, said his wrist injury came as a result of being handcuffed by a school police officer at Barton Hill Elementary School. He said the female officer grabbed his wrist, bent it behind his back and then handcuffed him.Anita Garcia said the incident happened three weeks ago, after her son was called to the principal's office regarding a separate incident at the school that he had witnessed. She is angry that she was not notified of the situation."I'm really upset because the school is his second home. He should feel safe there. He should not have gone through this. He's 11 years old," she said.She said her son is a good student without any disciplinary problems. X-rays taken last week revealed the injury."The officer was aggressive. If I would have done that to somebody's child, I would be in jail," Garcia said.The Los Angeles Unified School District said it is aware of the incident."As in all allegations involving the use of force-related injuries due to police action, this incident will be thoroughly and expeditiously investigated," said a statement released by the district's police chief Tuesday.LAUSD said that no other information can be released at this time. Garcia said she wants the officer to be held accountable and that she is considering filing a lawsuit against the district.