UNIONTOWN, Pa. -- A school bus driver was arrested after police said he sexually assaulted a mentally disabled girl.

Police said Jason Freeland assaulted the 16-year-old last month in the back of a school van.

Freeland works for Rittenhouse Bus Lines, which serves the Uniontown School District.

Uniontown school officials said they called police after a student told them her friend was "dating" a school bus driver.

"The bus contracting company that we deal with, we've dealt with them for over three decades. I'm sure they'll make the situation right. It's just a shame there are people in society that exist like that," said Uniontown Superintendent Chuck Machesky.

The owner of the bus company released as statement saying, "The safety of students is of the most utmost importance to us. We're in awe, shock actually."

Freeland is facing sexual assault and endangerment charges. He's been placed on leave from his job pending the outcome of the investigation.