Six students have been charged as a result of a brawl at Upper Darby High School this month in which a teacher suffered a concussion, township police said Thursday.

As many as 70 students were at the scene - captured on video - outside the school cafeteria, but most were not involved, said Michael Chitwood, the police superintendent.

Charges against the six include simple assault and reckless endangerment. An additional charge of aggravated assault was lodged against Jermaine Richardson, 18, accused of injuring the teacher and the only one charged as an adult.

He was being held at the Delaware County jail on $30,000 bail. The others were sent home. All six are suspended from school, Chitwood said.

The 30-year-old male teacher, who was not identified, suffered a torn ligament in his left leg in addition to the concussion, Chitwood said. "He tried to intervene in the fight and got knocked out," he said.

Chitwood said the Oct. 8 fight began with "bad blood on the school bus."

Richard F. Dunlap Jr., Upper Darby School District superintendent, said the school would not tolerate behavior that violates policies or endangers others.

"We want our schools to be a safe place where we can educated students," Dunlap said.

Chitwood said that after the school sent the video to police, he hoped to make a show of arresting the students. "We were going to take them out of school in handcuffs," he said, "but the school already suspended them."

"There's a lot of good kids in that school," adding that with 4,000 students, it was bigger than most Pennsylvania municipalities.

"There's a handful of knuckleheads that create an unsafe environment," he said.