Formal charges have now been laid against the 15-year-old student of Frome Technical High School in Westmoreland.
The teen is accused of being involved in an incident during which a female student of Petersfield High School, also in the parish, was fatally stabbed.
The ninth-grade student was charged with murder on Monday, almost a week after she was taken into custody following the deadly incident.
The police say the girl is scheduled to appear in the Westmoreland Juvenile Court today.
According to police reports, last Tuesday the girl visited the home of a schoolmate who was said to be recovering from injuries he sustained after being shot by gunmen.
While there, the other female student arrived, after which an altercation developed.
A pair of scissors was brought into play and the student from Petersfield High School was fatally stabbed.
The police were alerted and the Frome Technical student was subsequently taken into custody.