The 16-year-old gunman who opened fire inside a special needs classroom at Silver Rail Elementary School, killing three boys and a teacher was a former student at the Bend, Oregon school, investigators revealed Friday.

Bend Police Chief Mike Krantz identified the shooter Friday as Griffin John II, a Bend resident.

The teenager made his way into the school Thursday afternoon with a Maverick 88 12-gauge pump-action shotgun and opened fire in the classroom after he shot at a truck outside of the school, Krantz told reporters at a news conference on Friday.