MONTERREY, MEXICO — Chaos erupted inside a private school in Monterrey, Mexico Wednesday morning after a student opened fire inside his classroom.

Reuters reports that the incident began during a class at the American School of the Northeast, when a 15-year-old student suddenly pulled out a 22-caliber pistol.

CCTV footage shows the student, identified as Federico Guevara, first shooting a male classmate in front of him and then his 24-year-old teacher. He then went around the room and randomly shot at other students.

A total of seven shots were fired, some at point-blank range, before the teen turned the gun on himself. He shot at his temple but missed before running out of bullets.

After running back to his desk to reload his weapon, Guevara shot himself in the chin. His classmates rushed to the door as he lay in a bloody heap on the floor.

Guevara later died in the hospital. Three of his victims were hit in the head and are in critical condition. One took a bullet to the arm and has been declared stable.

Authorities believe the gunman brought the pistol from home and say it may be necessary to re-implement a protocol to have students’ bags checked when they enter school.