The altercation took place around 1:15 p.m. Wednesday, Nov. 2 inside a bathroom at Mount Vernon High School in Alexandria, Fairfax County Public School officials said.
A 15-year-old victim was taken to a local hospital with non-life-threatening injuries, according to a series of tweets by the Fairfax County Parents Association.
An underage suspect fled from the building, but was quickly taken into custody by county police, school officials said in a letter directed at Mount Vernon High School families.
Authorities say there is no further threat at the school, and the investigation remains ongoing.
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