Chicago mother says video shows son with autism body-slammed, injured at school T.J. said he was lifted five feet in the air and thrown to the ground.

 -- A Chicago mother of a student with autism said her son was attacked at school in a brutal bullying incident that was captured on video.

Gabrielle George said a video posted on social media Monday showed her 14-year-old son T.J. Harrer being picked up and body-slammed by another student at Lake View High School, located on the north side of Chicago.

Harrer -- who has autism, but functions well enough to attend public school -- suffered from a separated shoulder and head trauma in the incident, according to his mother.

George said the school told her that Harrer had fallen while playing around with another student, but witnesses said he was lifted at least five feet in the air and tossed to the floor.

She accused the school of downplaying the seriousness of the incident.

"What actually happened to my son was completely opposite the story that I was told," George told ABC’s Chicago station WLS on Tuesday. “Had I known that, I would have immediately come and got him. He should have been immediately taken to the hospital.

"If you saw the way he was thrown on the floor, he's lucky he didn't snap his neck," she added.

Harrer, a high school freshman who’s won numerous medals in the Special Olympics, said the encounter started with the other boy making fun of him.

"That's when they grabbed me by the chest and threw me down on the floor," he told WLS, adding that he barely knew the boy who assaulted him. Now, he says he is unsure about going back to the school.

"I don't want him to go back," his mother said. "I was promised they would protect him, that they would keep him from this very thing. And now, where do I go, where do I send him?"

Lake View High School Principal Paul Karafiol said he sent a letter to parents regarding the incident.

"I was very upset to see the video, but at the same time I was very proud of the fact that other students were the ones who brought it to our attention," Karafiol said in a statement to WLS.