(CNN) Jo Grayson said she was alarmed when her son, Thatcher, came home from his middle school covered in cuts and bruises.

Earlier in the day, Thatcher's teacher texted Grayson to alert her to an incident involving him. But it did nothing to prepare Grayson for what she saw hours later when Thatcher came home and she discovered the marks on his body.

After she obtained surveillance video that explained the marks, she became appalled. The footage shows Thatcher, who is autistic and mostly nonverbal, being dragged down a school hallway by his teacher and the school nurse.

"I just don't understand how someone can do this to a child, let alone to a person with disabilities," Grayson told CNN. "I want the school district to take action and not just install cameras in every room of each school, but also train their staff accordingly so they know how to handle children with disabilities, or rough situations with children like Thatcher."

Thatcher is a sixth-grader at Tates Creek Middle School in Lexington, Kentucky. Because of his condition, he's not able to tell his parents when something is wrong. But the photos Grayson posted to her Facebook account speak volumes.

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