SANTA CLARITA, Calif. — Two students are dead and four others are injured after a student at a California high school opened fire on his classmates on Thursday, according to officials, as authorities seek answers for the reason behind the shooting.

It happened just before classes began at Saugus High School in Santa Clarita, about 30 minutes northwest of Los Angeles.

Authorities say it took 16 seconds for the 16-year-old student, whose identity has not been released but authorities described him as an Asian boy dressed in black, to shoot five of his classmates, before investigators say he eventually shot himself.

Los Angeles County's Sheriff says the 16-year-old suspected gunman is in critical condition. His name has not officially been released.

Two of those classmates shot, a 16-year-old girl and a 14-year-old boy, died at the hospital. Three other students were taken to the hospital with gunshot wounds.

Authorities says the student used the last bullet from a .45 caliber semi-automatic pistol on himself.

The shooting happened about 7:40 a.m. before school started.

Students say they were tripping over each other to get out of the school, some even running to nearby homes to ensure their safety.

One student who was near the shooter when it happened describes what she saw.

"He was wearing black sunglasses at the time, and he looked very familiar. And then he shot two people and I saw that happen, I just saw him fire — one, two, three — and then I knew I needed to get out of here,"  said Micah Turner.

Investigators say they are still trying to figure out what exactly led to the shooting, at this point there appears to be no clear motive, but they say they did find a post on what they believe to be the shooter's Instagram account which said quote "Saugus have fun at school tomorrow."

Investigators are working to identify reported threats they say the shooter may have made on social media.

They say anyone who sees any threats online should report those immediately.