CHANTILLY, Va. — Fairfax County police used an electronic shock device on a 16-year-old Chantilly High School student who police say threatened to harm himself and others on Monday.

According to police, after the student became aggressive with school staff, the school resource officer tried to negotiate with the student. When that failed, other officers were summoned.

Police say the student got more aggressive as officers tried to handcuff him. “Unable to gain control of the student after one hand was cuffed, one officer used an electronic control weapon in drive stun mode to attempt to gain control of the student,” according to a statement from police.

Police say that when the device, or ECW, is used in “drive stun mode,” no darts penetrate the recipient’s skin, but pain serves as a distraction. Other modes are capable of causing uncontrolled muscle contractions.

Even after both cuffs were on, police say the student continued to try to hurt himself by banging his head on things.

The student was not injured and was taken for a mental health evaluation.

No charges are being sought, according to police.