BAINBRIDGE ISLAND, Wash. -- A mother is outraged after her developmentally-challenged daughter was left on a school bus for nearly three hours.

"There's anger. There's outrage. There's hurt, just sadness," Sarah Rowe said.

Rowe put her 4-year-old daughter, Ava, on a small bus around 11:15 a.m. on Wednesday. The bus driver dropped off two kids at Ordway Elementary School, returned to the bus barn, and forgot all about Ava, even though the driver was only responsible for three passengers.

Ava sat in a car seat on the bus, alone for three hours. The shy young girl has speech apraxia, a neurological disorder that hinders her ability to speak.

When the bus dropped Ava back at home, her mother noticed something was wrong. Her daughter looked sad.

"She (my daughter) said, 'She (the driver) left. She said, 'I waiting, and waiting, and waiting.' And she told me again and again. She cried, and cried, and cried," Rowe said. "Eyes all puffy and really upset. With her speech apraxia, she really couldn't verbalize what was going on."

Officials from the Bainbridge Island School District called about an hour later and admitted the driver had made a mistake by failing to follow procedure.

Superintendent Janet Chapel said the bus driver didn't walk through the bus as instructed, but she doesn't know why.

"I don't know if there's an explanation. It certainly did not happen," she said.

And it appears the driver wasn't the only one who didn't follow procedure. Ava's teacher did not notice she was absent, even though teachers are instructed to check attendance.

"That procedure was not followed," said Sarah Rowe.

Sarah Rowe demands to know why the bus driver still has a job. The driver has been placed on paid administrative leave, but the mother believes she should be fired.

"Absolutely. Now. This second," she said.

District officials expect to wrap up their own investigation into the matter over the next few days.