Two Delaware County high school students have been charged in a school-bus assault that was captured on a video that went viral.

The two, from the County Alternative School, were charged with aggravated assault, simple assault, terroristic threats, and related crimes, District Attorney John J. Whelan said Wednesday.

He did not release the names of the juveniles. "We did not charge them as adults," he said.

Whelan said an incident at the school shortly before the students boarded a Southeast Delco School District bus last week precipitated the taunting of two male students by two others. A female student also was being questioned by police, Whelan said, but has not been charged.

The video showed one student hitting another in the head numerous times. The beating continued when the student stood and struck the victim in the face, causing a bloody nose, Whelan said.

"It is very disturbing to see," he said, adding that parents expect their children to be safe at school or on the bus.

The incident occurred in Chester, Whelan said, but no Chester residents were aboard the bus.

The victim was treated at Taylor Hospital, he said.

"There is no way the bus driver wasn't aware of this," he said. The driver should have pulled over and contacted police, he said, adding that the district needed a protocol for such incidents if it did not have one already.

The school is part of the Delaware County Intermediate Unit.

On the unit's website, the school is described as "a full-day special-education program ... designed to provide a new educational experience for students who have had significant difficulties in previous school placements."

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