Police have arrested a 16-year-old boy and charged him with firing a BB gun rifle with a scope at a school bus on Brown Street in Westbrook Monday afternoon.

Authorities said Wednesday they believe an adult was also involved in the shooting. No additional details were released. The case is being sent to the Cumberland County District Attorney.

Westbrook Police Chief Paul McCarthy said detectives arrested the boy at his King Street home on Tuesday and charged him with reckless conduct with a dangerous weapon and violation of probation. The boy was taken to Long Creek Youth Center in South Portland. His name has not been released due to his age.

The arrest was good news to the mother of an 8-year-old girl slightly injured in the incident. She said Wednesday it eased fears among neighborhood parents and children who ride that bus.

“It makes me feel 10 times better,” said Heather Sanborn, whose daughter, Shelby Ames, 8, was on the bus and sustained four small cuts.

Westbrook police said the BB gun rifle was fired at the slowly moving school bus at approximately 3:50 p.m., breaking a window. The bus was carrying home Prides Corner School students in kindergarten through third grade.

Ames, a second-grader, was sitting beside the bus window that was smashed. “I heard the window break,” Shelby said.

Ames said her friend was crying and kids were scared. Ames was treated by Westbrook emergency medical technicians in an ambulance at the scene.

“They got the glass out at the scene,” Sanborn said, who added her daughter had four little cuts on her hands.

Another child hurt her head. “A girl was struck on the forehead with what we believe was glass,” McCarthy said. “She was treated at and released to her parents. She appears to be OK at this point.” Police did not release the girl’s name.

“A little girl in the rescue cried because she didn’t know where her mother was,” Sanborn said.

The driver of the bus, Bruce Ibarguen, said he made a normal stop at the intersection of King and Brown streets and the children there got off the bus safely.

Interviewed at the scene, Ibarguen said he had just started moving the bus when it was hit. “I heard a whistling noise,” he said. “Children on the bus thought someone threw a rock.”

Ibarguen said he pulled the bus over right away when he realized it had been struck. He said there were about 48 children on the bus when it was struck.

Ibarguen said he rushed to the girl that was struck and saw that she had a bump on her forehead. He said the mother of one of the children at the bus stop ran and got ice for the girl.

Sanborn learned about the incident from her mother when she arrived home from work. “I was screaming,” Sanborn said.

A friend, Angie Tucker, rushed Sanborn and Shelby’s sister Shania Sanborn, 10, to the scene.

“We were both crying,” said Shania, a third-grader at Congin School.

When they arrived, the roads were blocked but police let her through. Shelby was standing near an ambulance.

“I ran up and grabbed her and hugged her,” Sanborn said. “Shelby was scared and wanted to go home.”

The incident frightened people along Brown Street. Cassie Doughty, 13, was playing down the block when the bus was struck. “I heard a pop,” she said, adding she didn’t see who fired the gun or where the shot came from.

Doughty said she initially thought the incident was worse than it actually was.

“I thought it wasn’t a BB gun, I thought it was the real thing,” she said. “Kids on the bus were screaming and some were crying.”

Tevin Lopez, 14, was playing outside nearby when the incident occurred. “I thought someone got shot on the street,” he said.

Sanborn described Monday as difficult. “There’s a bunch of little kids on that bus going through a lot,” Sanborn said.

Sanborn took her daughter to school Tuesday, but let her ride the bus home. Sanborn said children on the bus Tuesday were scared and wanted to sit near the bus driver.

Sanborn hopes parents would think twice before buying their kids a BB gun.

“I thought Westbrook was safe. It’s becoming bad, what’s next?” Sanborn said Tuesday before the arrest was announced.

Ibarguen said the incident was an unpleasant reminder of his past.

“I moved from Guatemala to Maine to get away from violence in 1971,” he said.

Detective Steve Lyons credited work by Detective Sean Lally and evidence technician John Hanlon as leading to the arrest. “We put all our resources there yesterday,” Lyons said Wednesday. “We were very concerned.”

Cutline – Westbrook Police Chief Paul McCarthy (left) speaks with Bruce Ibarguen, the driver of the school bus that was struck by a pellet gun on Brown Street Monday afternoon. (Shelby Ames 1) Boy charged, kids frightened in bus shooting