Teen accused of Oregon elementary school shooting has been identified by police as new details are released

A 16-year-old has been identified as the alleged gunman responsible for the shooting at an Oregon elementary school on Thursday (October 15).

Senior law enforcement officers have identified the alleged perpetrator as John J. Griffin II, who was fatally shot by an armed bystander who interrupted the abhorrent attack.

A 'community member' is reported to have fatally shot the teen attacker. Dispatch audio suggests it was a father of a child at the school who 'neutralized' the shooter 'within about five minutes', CBS News reports.

Police claimed the gunman gained entry into the school by shooting through a locked door around 1pm local time.

NBC News was later informed by officials that the teen’s mother had purchased the long gun used in the shooting around his birthday.

Three children who attended Silver Rail Elementary School in Bend, Oregon, were killed during the attack, as well as a teacher.

Another child, 7, remains in a critical condition.

The gunman took the lives of four victims at the school. (Payton Bruni / AFP via Getty Images)

Oregon Senator Jeff Merkley has asked people to 'hold the students, teachers, families, and entire Silver Rail Elementary School community in your hearts' as details begin to emerge.

Following the devastating attack, witnesses have been coming forward to share their accounts of what they saw unfold.

Caleb Weis, who spoke to ABC News following the vicious shooting, said that police were 'piling in' following the emergency call.

"Every first responder I've ever seen, all the agencies, you've got country sheriff, the city police, and the state police all simultaneously responding," he shared.

"It almost looked automatic. Everywhere they were staging, everything they were doing seemed like they were every highly trained."

Details are beginning to emerge about the devastating crime. (Payton Bruni / AFP via Getty Images)

Bend Mayor Melanie Kebler also expressed her condolences in a statement, admitting she was unable to 'make sense of' the profound loss felt across the state.

"We grieve alongside you and we will get through this together," she added.

Oregon has a number of laws regulating firearm ownership and sales, although the state does not require a general licence or safety training to purchase or possess a gun under its existing rules.

The state prohibits anyone under 18 from purchasing a firearm, although minors may be permitted to use or possess one with parental consent for activities such as hunting.

Police, who are also working alongside federal investigators, have not publicly identified a motive for the tragic events that unfolded on Thursday.