A California woman is suing a Los Angeles school district alleging her son was left with permanent brain and spinal injuries after another student choked him during a bullying incident last year.

The mother said her son, who was 12 at the time and a sixth grader at Animo Westside Charter Middle School, was "brutally assaulted and strangled" in January 2018 by a 14-year-old who allegedly had been violent toward other students, according to the lawsuit filed Monday in the Los Angeles County Superior Court.

The mother, who does not want to be identified, claimed school officials were aware the 14-year-old had been involved in an incident prior to the one when her son was attacked and “failed to take adequate action in order to protect the other students at the school.”

Surveillance video from the January 2018 incident shows the alleged bully punch the 12-year-old boy in the stomach and then push him up against an outside wall. He then appears to put his hand around the 12-year-old's neck as other students crowd around them.

A female staff member walks by and looks at the group before walking away. The 12-year-old boy then falls to one knee and appears to be struggling to breathe.

Another video from inside the school shows several people carrying the boy into the office and laying him on the floor before paramedics arrive.

According to the lawsuit, the boy had several seizures and 911 was not called until after his mother arrived at the school, which was about 30 minutes after the incident.

The mother alleged that staff members at the school did not immediately tell her what happened to her son, and she learned from other students that he had been choked.

Her lawyer, Ben Meiselas, said in a statement to NBC News that staff members did not handle the situation properly.

“The staff did everything wrong, every step of the way, and showed a callous disregard for my 12-year-old client’s life and well being," he said. "This is unacceptable and every adult working for this school should be haunted by their conduct for the rest of their lives."

The mother told NBC Los Angeles that her son has been struggling since the incident, and doctors recently told them that he has permanent brain and spinal injuries stemming from being choked.

Meiselas told NBC News that the boy will have to be monitored for the rest of his life and now requires assistance to read and write.

"He is not the same anymore," the mother told NBC Los Angeles. "Every day, it has been a daily struggle."

The mother is suing the Green Dot Public Schools district for negligent supervision and infliction of emotional distress.

The district told NBC News in a statement that it has not been served with a lawsuit, but said it was concerned by the incident.

"We take seriously the safety of all our students and quickly address bullying of any kind on our campuses," a spokesperson said. "Green Dot is committed to working to ensure all our students receive a quality education in a safe environment where they can learn and grow."

The mother told NBC Los Angeles she did not want to press charges against the student but wants the district to expel him.

Green Dot Public Schools is a network of public charter schools serving Los Angeles and recently expanded to include schools in Tennessee and Washington state, according to the district's website. Microsoft co-founder Bill Gates and his wife, Melinda, through their foundation, have donated millions of dollars to the district.

A spokesperson for the Bill & Melinda Gates Foundation said in a statement that it is not involved with the district's management.

"We believe all schools should provide a safe and welcoming environment for students and should have no tolerance for bullying or violence of any kind," the statement read.