PITTSBURGH -- More than a dozen girls started fistfighting after an early dismissal on the last day of classes Monday at Peabody High School.

The altercation started on school grounds around 10:30 a.m. and continued on the streets of East Liberty. The student who shot the footage said she wasn't in school that day, but went there when classes let out because she and others had heard there would be fights.

Click here to see exclusive home video of the brawl.

Click here to view images from the fight.

Robert Fadzen, chief of safety for Pittsburgh Public Schools, said some end-of-school enthusiasm merely got out of hand. He said police haven't seen anything worse than water balloons and water guns on the last day of classes in the past.

But students said it has become somewhat of a tradition for girls to settle their differences this way. They said it was well-known that the violence was being planned.

"People knew this was coming because it almost happened on Friday. They should have known that it was going to be the last day of school and there was going to be fighting everywhere," student Marcie Rucker said.

"There were students talking the whole year about their enemies and how they're going to fight. It happens every year," said another girl, who didn't want to be identified. "They're going to fight at the end of the year, and they just fought today."

Fadzen said there is no annual end-of-year fighting tradition in the city schools.

No one was seriously hurt, but one girl was treated at a hospital after being pepper sprayed. The video appears to show her holding her eyes after already being sprayed. As an officer attempted to handcuff the girl, another officer appears to spray her again. She is taken to her knees and handcuffed.

Some witnesses thought the officers used unnecessary force.

"They put her in handcuffs and one of the policemen threw her on the ground," one witness said. "I was thinking, 'Why should he have to throw her on the ground when he's a man and she's a slim girl?' He shouldn't have to do that, I didn't think."

Fadzen said the force used by officers was not excessive.

Though a dozen or more girls were fighting, only one was arrested for disorderly conduct. Another girl was cited for failing to disperse. Four boys who never threw a punch were also cited for failing to disperse.

Police and students think the fight was a one-time incident that will not be repeated.