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A 16-year-old girl, a 14-year-old boy, and a gunman have been killed and three others injured during a 16-second gun shooting at Saugus High School in Santa Clarita, north of Los Angeles, California on Thursday.

The attack came on the suspect's 16th birthday, identified as fellow student Nathaniel Berhow by the U.S. press. The perpetrator died a few hours later after he shot himself in the head.

Students and teachers spoke about how they barricaded themselves in classrooms amid chaotic scenes, conducting an active shooter drill that has been adopted by many schools in recent years following deadly attacks across the world.

On Thursday, LA county sheriff Alex Villanueva said the incident was first confirmed 07:38 a.m. local time, adding that officers were on the scene within two minutes.

Police officials said the suspect stood in the school courtyard when he took a semi-automatic 45-caliber pistol from his backpack and opened fire for about 16 seconds before turning the gun onto his head.

For more than an hour, students barricaded themselves in classrooms while police tried to determine whether the gunman was still at large.

Investigators confirmed that there was no known connection between the attacker and the victims but the attack came on the 16th birthday of the suspect. The FBI said it seemed that he was acting alone and that he was not affiliated with any particular group or radical philosophy.

A fellow student, Brooke Risley, told the Associated Press that the perpetrator was introverted but "naturally smart," adding that he had a girlfriend and was a boy scout. Reports also confirmed that the boy lived in a modest home nearby, and that two years ago his father died. Investigators have interviewed the shooter's mother and girlfriend. A neighbor also said the boy had been dealing with the death of his father.

A Senate discussion on gun control law transpired when the attack news broke. Senator Richard Blumenthal, a Democrat, called for gun control as he read about the news. He said that the legislation "is not just a political responsibility, it is a moral imperative."

Gun control and the right to bear arms in the United States is a divisive political issue. According to a 2017 study, about 40% of Americans say they own a gun or live in a household with one, and the rate of firearm-related murder or homicide in the nation is the highest in the developed world.

Nearly 230,000 teenagers in the U.S. have witnessed gun violence at school since the Columbine High School shooting in Colorado in 1999, according to the Washington Post.

Since 2018, the U.S. publication Education Week has reported school shootings. It says 22 events have occurred so far in 2019 that resulted in death or injury.

The Everytown gun control advocacy group said Saugus was the 85th incident of gunfire at a school this year. The group explained that the most important thing schools can do to avoid active shooter incidents, and overall gun violence, is to interfere before an act of violence is committed by a student.

To do this, schools are encouraged by Everytown, AFT and NEA to establish threat assessment initiatives and set up threat-assessment teams in their schools.

The teams are generally made up of multi-disciplinary investigators that are specifically trained to intervene in the early warning signs of potential aggression and direct those who injure themselves or others to appropriate treatment. School safety experts must also be a part of this threat-assessment group.

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