Disturbing video shows a 13-year-old boy's backpack getting caught in the doors of his school bus, then being dragged nearly 175 feet as the bus drove away. Now his mother is suing the Utah school district, saying the bus driver intentionally dragged her child because he's biracial.

Brenda Mayes claims that the Davis School District bus driver has had a history of "racial animus" towards biracial children, and that animus almost led to her child being seriously injured, according to a lawsuit filed Tuesday with the U.S District Court Northern Utah Division.

Video given to NBC News by Mayes' attorney shows the incident from February in which Mayes' son was departing the bus at West Point Junior High, roughly 30 miles north of Salt Lake City, when the doors closed on his backpack. The bus then moves, dragging the boy for what Mayes' lawsuit estimated to be 150 to 175 feet.

Mayes claims in her lawsuit that her son was subjected to racial discrimination, harassment, assault and bullying by the bus driver in violation of Title IX and Fourteenth Amendment protections.

The district, the county's transportation director and the bus driver are all named as defendants in the case.

Had the boy's backpack straps broken, he "would have dropped to the pavement and could have been run over and killed by the bus or could have sustained serious injuries by the fall onto the concrete," the lawsuit said.

"He could’ve been crushed," Mayes told NBC News on Thursday. "That wheel would’ve crushed him, one turn could’ve crushed him."

Mayes filed a complaint against the bus driver, John Naisbitt, but says nothing was done when she first brought up the incident with school officials. The transportation director, Dave Roberts, was dismissive of her complaints, Mayes said.

Naisbitt retired while the district was investigating, according to the lawsuit. The school district confirmed in a statement he no longer worked for them.

"All I wanted was them to change some type of policy," Mayes said. "Honestly got blank stares, no response, no anything."

She told NBC News this is not the first such incident involving Naisbitt.

In October 2018, Mayes claimed that he closed the doors on a neighbor's child, and attempted to do the same with her younger son.

Her lawsuit also claims that parents made complaints about Naisbitt in 2017 after he allegedly berated the children on the bus, called them names, and refused to take them to their assigned bus stops.

Davis School District said it could not comment on the lawsuit because it had not yet been served.

“However, when issues of discrimination are raised at any time, they are investigated thoroughly," the district said in a statement. "The Davis School District takes any claims of racial discrimination seriously and does not tolerate any form of racial discrimination in our schools."

NBC News made attempts to contact John Naisbitt, but phone numbers connected to him through public records appear to be disconnected.

Naisbitt spoke to Fox13 News in Salt Lake City on Tuesday and said he didn't see the boy caught in his doors. Naisbitt said he warned kids he would be moving because other buses were lined behind him and claimed the incident was staged after he disciplined the boy's younger brother.

He denied being a racist.

“Not at all. No. Look at my dog. He’s as black as could be,” Naisbitt told Fox13 News.