A 16-year-old shooter killed three children and a teacher at Silver Rail Elementary School in Bend, Oregon on Thursday afternoon before a community member shot and killed him, police said.

The suspect forced his way into the school by shooting at locked doors around 12:59 p.m. local time, according to Bend Police Chief Mike Krantz. The first emergency call reported an unknown suspect firing a long gun at a vehicle outside the school. Photos showed a red truck with bullet holes. Within minutes, dispatch received 911 calls that the attacker had entered the building.

The three children killed were ages five, eight and eleven. A seven-year-old child and a 54-year-old teacher were hospitalized in critical condition, Krantz said. Police did not identify the victims or provide additional details about the attacker.

A bystander saw the shooting unfold, pursued the attacker into the school and engaged him, killing him before law enforcement arrived. Officers reached the scene three minutes after the shooter opened fire and confirmed he was dead before conducting a search of the building.

Police have not disclosed whether the attacker had any connection to the school. The suspect was identified as a local 16-year-old but authorities released no further information about him.

Steven Cook, the top administrative official of the Bend school district, released a statement: "We are stunned and heartbroken by this senseless tragedy. No words can adequately express the grief our community is experiencing."

Silver Rail Elementary serves approximately 450 students and employs more than 40 staff members. Schools in Bend were closed Friday to allow the community time to heal.

According to the K-12 School Shooting Database cited by police, there were 235 shooting incidents at American schools last year and at least 140 incidents so far this year.