The boy was charged on May 22 after a school resource officer at Unity Reid High School found him with the weapon on May 1 around 11:10 a.m., while investigating a separate incident, county police said.
The SRO determined the knife was not part of any threat to other students, faculty, or staff, police said.
Following the investigation, officers sought petitions against the accused, identified as the 15-year-old male student. After consultation with Juvenile Court Services, the case resulted in formal action and will be handled through the court process at a later date.
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