CHARLOTTE, N.C.--We are learning more about a group of guys that walked onto a Charlotte high school campus and threatened a student. 

One of the suspects, a 17-year-old, has been arrested numerous times, including last year for having a gun on school grounds. 

The incident happened last Monday at West Charlotte High School in a mobile classroom just after 3 p.m. 

The police report describes the incident as a "group of kids" but the mother of the victim tells us the people who threatened her son were not all students.  She also mentioned possible gang activity. 

The school resource officer declined to speak with us.  A CMS spokesperson says "We have launched an investigation to find out who the kids were that came on campus.  We've added extra security during afternoon hours to help keep students and staff safe." 

Charlotte-Mecklenburg Police have arrested one person in connection to the incident.  Mark Ellis faces a trespassing charge. 

Jail records show the 17-year-old has been charged 18 other times since last February.  Those charges include robbery, assault, possession of a stolen firearm and having a weapon on school grounds.