CHANTILLY (CBSDC) — The tranquility and light-hearted mood of the last day of school was shattered Friday when two students were shot with a BB gun near Rocky Run Middle School in Chantilly.

A 14-year-old male and 13-year-old female suffered non-life threatening injuries in the shooting, which occurred around 10 a.m. They were taken to Inova Fairfax Hospital.

Police and school officials immediately locked down the school and searched the grounds.

Within a half hour authorities were able to apprehend a group of four teen-agers whom they believed were related to the shooting.

A motive for the shooting was not immediately made clear.

The shooting occurred on school grounds, but outside of the building. A group of students were outside of the building for an end of the year celebration at the time of the shooting, per ABC 7.

Authorities are continuing to investigate the incident. Charges against the suspects are pending.