The shooter who killed two classmates at Saugus High School in California died from his injuries Friday, the Los Angeles County Sheriff's Department said in a statement. Nathaniel Tennosuke Berhow, 16, was being treated for a self-inflicted gunshot wound to the head, authorities said, and his mother was with him when he died.

On Thursday morning, Berhow pulled a handgun out of his backpack at the Santa Clarita school and shot five of his fellow students before turning the gun on himself, authorities said.

"We didn't know if the shooter had a clear view of us or not, we just sprinted and we just like prayed for our lives," one student told CBS News. "I actually thought I was going to die."

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Gracie Muehlberger, 15, and Dominic Blackwell, 14, were killed; the other three victims are expected to survive. Two of the victims, Mia Page Tretta and Addison Koegle, were released from the hospital on Saturday.

Authorities said it's not yet clear why Berhow carried out the deadly assault, which occurred on his sixteenth birthday. He did not leave behind a diary or a manifesto, and he has not been linked to any violent ideology or group.

They do, however, believe the attack was planned, citing the fact that Berhow used the last bullet in the gun to shoot himself. It's not clear how Berhow obtained the gun — authorities said it was not one of the six guns in his home registered to his deceased father, although they noted that there were also several unregistered firearms in the home.

Micah Turner, a sophomore, told CBS News she witnessed the shooting firsthand. "He shot two people and I saw that happen," Turner said. "I just saw him fire one, two, three and then I knew, I was like I needed to get out of there."

When asked what moments would stay with her, Turner said "His face, and just seeing that one person fall."

"It's going to be hard to forget," she added. "But I'm gonna have to live with that sight in my head."

Jonathan Vigliotti contributed to this report.