Administrators at Freedom High School in Woodbridge called the student resource officer on May 18 after they found the weapon in the student's possession, Prince William County police said.
The student never brandished the knife or threatened to use it. The teen had violated another school policy and administrators found it during their investigation, officials said.
Police arrested the boy on Friday, May 27, and charged him with possession of a weapon on school property, and transported him to the Juvenile Detention Center.
Police do not release the names of juvenile suspects.
The incident was the second time last week that Prince William County police arrested a Woodbridge high school student for bringing a weapon to class.
On Wednesday, May 25, a 15-year-old Woodbridge Senior High School student was stabbed after he pulled a knife during a fight in a bathroom.
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