By Walt Hunter, Elizabeth Hur

SHARON HILL, Pa., (CBS) — New developments out of Delaware County after video surfaced of a school bus attack.

Late Monday, police confirmed to Eyewitness News that investigators are in the process of filing criminal charges against three students and the bus driver. The charges could be filed as soon as Tuesday.

The video shows one of two students — beaten on the bus — on their way home from school. It was first posted on Facebook and shows Dylan Fonner being punched in the face aboard a school bus from the Delaware County Alternative High School Wednesday afternoon.

Jackee Fonner, Dylan’s mother said, “I wanted to hug my son because I saw him after he got beat up, but then after watching the video, I couldn’t believe it was that bad.”

Pictures provided by Dylan’s mom show, she says, a swollen nose, three chipped teeth and other facial injuries.

Neighbor, Judy Bair said, “Why didn’t the bus driver, I can’t understand how he can sit there and see this happen and not put a stop to it? I know things happen on a bus but kids will be kids but this went too far, it really did.”

Among the questions from those who know the 17-year-old well: why the video does not show the bus stopping or the driver intervening?

“Very frustrating and very angry because our children are supposed to be safe and now it’s not only do you have to worry about your child being safe in school but now you have to worry about the bus ride too,” Dylan’s mom said.

Beyond confirming an investigation is underway, the school district solicitor is not commenting on the procedures followed by the driver or the students allegedly involved.

Meanwhile, late Monday, Chester Police Commissioner Joseph Bail confirmed to Eyewitness News, Chester police detectives are in the process of filing criminal charges against three students and the bus driver. We’re told the case could be presented to the Delaware County District Attorney’s office as early as Tuesday.