NEWBURGH, N.Y. (CBSNewYork) — A six-year-old boy with autism was left behind on a school bus in upstate New York.

The child and his mother spoke exclusively to CBS2’s Ali Bauman about their frightening ordeal.

Little Armani Johnson was busting with energy Thursday night, but on Monday morning he fell asleep on the ride to Meadow Hill Elementary School in Newburgh.

“He’s vulnerable, he has autism, and he doesn’t know,” his mom, Roxanne Mendoza, said.

Roxanne found out about the mixup about eight hours later, when the school called.

“You gotta be kidding me,” she said. “What happened, and why am I being called at three in the afternoon?”

She says she was told someone spotted the little boy on a security camera. Since then, she says she’s been calling and emailing the school every day looking for answers.

“(It’s) like playing ping pong,” Roxanne said. “The school said this, and the bus company says another thing, and no one’s giving me answers.”

The school caims Armani was never alone on the bus. After all the other children were dropped off at school, the superintendent’s office tells CBS2 that Armani’s bus went back out to pick up preschool students who have a later start time.

Faculty found Armani about an hour later, after the preschool children got to school. His mom says with his autism, her son struggles whenever there’s a hitch in his routine.

“He didn’t know where he was, who he was with,” Roxanne said. “The next day I had to let him know it’s okay.”

The school says bus monitors are supposed to check for sleeping kids at the end of each route.

“We entrust our children to the public school system, and the buses contract for our children to be safe,” Roxanne said.

The bus company told CBS2 in part, “There was an aide on the bus, she was terminated immediately.” The school also said staff acted quickly to ensure Armani continued with a normal school day.