OLYMPIA, Wash. (AP) — A school bus driver has been placed on leave while the Olympia School District investigates accusations that he bullied a developmentally disabled 14-year-old girl.

The Washington Middle School student has been complaining about verbal abuse for more than a year but the district didn’t act until it saw video from a surveillance camera, her mother told The Olympian.

The district showed the mother video taken April 17 that shows the driver encouraging other special-needs students on the bus to call the girl names.

“You can clearly hear the driver calling my daughter names, encouraging other children to bully her,” the mother said. “All of the children on the bus are special needs with a variety of disabilities, which makes it even worse.”

The girl was recently frightened by a bee on the bus, and on the video the driver says he will bring a beehive on the bus, according to the mother.

The girl has an assigned seat at the back of the bus, where the heaters are located. When she has asked the driver to turn the heat down, he instead turns the heat up, the mother said.

The school district is treating the complaint very seriously, a spokeswoman said.

“We learned about the inappropriate verbal exchanges last week and immediately put the driver on leave. The district is now conducting an investigation. In the meantime, staff is committed to working with this family to ensure the student feels safe and supported on her way to school, at school and on the way home from school,” spokeswoman Rebecca Japhet said in an email Monday.

The school district has refused to release a copy of the videotape. The mother has been in contact with a lawyer