Members of law enforcement walk at Saugus High School after a shooting at the school on Nov. 14, 2019 in Santa Clarita, California. (Mario Tama/Getty Images)

A 16-year-old Saugus High School student who shot five other students on the Santa Clarita campus before turning the gun on himself on Thursday morning has died.

Saugus High School junior Nathaniel Tennosuke Berhow, 16, died at 3:32 p.m. Friday, according to the L.A. County Sheriff's Department, which identified him as the assailant. The department noted that Berhow's mother was present at the time of his passing.

The L.A. County coroner's office has confirmed to KPCC/LAist that Gracie Anne Muehlberger, 15, was one of two teens killed in the shooting, and that 14-year-old Dominic Blackwell was the other. Three other students were injured.

The attack was planned and deliberate, according to Villanueva, but the shooter appeared to have targeted his victims "at random," the sheriff added.

"It wasn't a spur-of-the-moment act," he said, though the motive "still remains a mystery."

The shooter released no manifesto or any other writings indicating his plans, Capt. Ken Wegener of the sheriff's homicide bureau said at an afternoon briefing.

On Thursday investigators said that an Instagram account they thought belonged to the suspect was used to post the message, "Saugus have fun at school tomorrow." After working with Facebook overnight, authorities have determined the account was not linked to the shooter. The account was deactivated by Facebook for violating the company's terms of service.

Wegener added that the account was created by an individual outside of the U.S., but did not provide further details.

On Thursday morning, the shooter's mother dropped him off at school with no idea her son was carrying a .45-caliber semi-automatic pistol in his backpack, according to authorities. Investigators say the teen boy said nothing before pulling the gun from his bag and shooting five of his classmates, saving the last bullet for himself.

Prayer candles, balloons and a teddy bear remain at the scene of a memorial at Santa Clarita's Central Park on Friday, the day after a Saugus High School student brought a gun to campus, shooting five classmates and fatally wounding two before turning the gun on himself. (Kyle Stokes/LAist)

Santa Clarita Valley Sheriff's station detective Dan Finn was dropping off his girlfriend's son at school when he saw hundreds of students running away from campus, Finn said at a press conference.

A student told Finn that there were gunshots on campus. Finn went toward campus, going around the administration building into the quad, where he saw three victims on the ground.

Finn wasn't aware at the time who the shooter was, he said.

Other off-duty officers from the Inglewood and L.A. police departments, along with the school administration, were also on scene quickly and administered first aid.

Finn said that he had an administrator retrieve a medical aid bag, packed the wounds of victims, and tried to stabilize them.

At least two of the wounded students were able to run to nearby classrooms after being shot, according to sheriff's officials.

Investigators have conducted over 40 interviews and have several more pending, according to Wegener, who urged anyone with information to come forward and contact the department's homicide division at 232-890-5500.

Villanueva said authorities recovered six guns registered to the shooter's deceased father, whose obituary noted his interest in big game hunting. In addition, the sheriff said authorities found other firearms — some unregistered — at the home. None of those weapons were used in the shooting.

Santa Clarita Mayor Marsha McLean acknowledged the bravery of the students directly affected by this attack, as well as fellow students who came to their aid.

She also noted that a website, saugusstrong.org, was being launched as a community resource for families, friends and community members affected by the tragedy.

"We have a lot to process in the coming days, weeks and months, but we will get through this together," McLean said.

The school had held an active shooter drill in recent weeks, according to sheriff's officials.

It remained a crime scene Friday morning, but has since been processed, cleaned and released back to the William S. Hart Union School District. It's unclear when the campus will reopen, and all other district schools were closed Friday.

HOW WE'RE REPORTING ON THIS

Reporter Kyle Stokes is providing coverage from Saugus High School. Reporters Mariana Dale and Jacob Margolis are providing coverage from Santa Clarita to learn more about the victims. Reporter Robert Garrova is looking into immediate first aid efforts. Reporter Elly Yu will be providing coverage about the suspect's family life. Digital producers Ryan Fonseca, Mike Roe, associate editor Lisa Brenner and engagement producer Elizabeth Robinson are keeping this story updated. Additional research and reporting is being done by KPCC newscast producers.

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NOTE: This developing story will be updated frequently. This post was initially published at 11:12 a.m. Friday, Nov. 15.