NORFOLK, Mass. — A school bus driver in Norfolk was arrested Friday after students found a handgun that police say he had accidentally dropped.

David Tripp, 65, of Norfolk, faces charges including reckless endangerment of a child and carrying a firearm on a school campus. He was being held by Norfolk police and is expected to be arraigned Monday.

Police say they received a call Thursday from a parent whose child saw the gun while getting on the bus at King Philip Middle School. An investigation found that the gun had been on a seat in the back of the bus as students were boarding. None of the students touched it, police said.

After hearing a commotion, the driver retrieved the gun and put it in his pocket, police said. He continued on the route and did not report the incident to police or school officials. There were about a dozen students on the bus at the time.

Police said the gun had fallen out of Tripp’s pocket while he was cleaning the bus. Officers arrested him at his home on Friday.

It was not immediately clear whether Tripp has obtained an attorney to comment on his behalf.

Tripp’s license to carry a firearm has been suspended and any guns he owns are being seized. Police already confiscated the handgun and said it was loaded with seven rounds.

Tripp was working for Holmes Bus Company, which operates buses for Norfolk Public Schools and the King Philip Regional School. He has been barred from transporting students in both districts. The bus company did not immediately respond to a request for comment Saturday.

Norfolk Public Schools Superintendent Ingrid Allardi said she was “furious” and will demand that Tripp be fired.

“I was horrified to learn about this incident and it is unconscionable that a person would bring a firearm onto a school bus full of children, let alone someone whose care of those children had been entrusted to them,” Allardi said in a statement.