Nathaniel Tennosuke Berhow, 16, the suspect in Thursday’s deadly shooting at Saugus High School, died at 3:32 p.m. Friday, according to Los Angeles County Sheriff’s Department officials.

Berhow’s mother was with her son at Henry Mayo Newhall Hospital at the time of his death, officials said.

The two teenagers who died in the shooting have been identified by Los Angeles County Coroner’s officials as Gracie Anne Muehlberger, 15, and Dominic Blackwell, 14.

LA County Sheriff Alex Villanueva identified Muehlberger at a midday news conference Friday also attended by Santa Clarita Mayor Marsha McLean and other city officials.

“The 14-year old-boy is the nephew of one of our security officers,” Villanueva said in an interview Friday with Los Angeles TV station KNBC.

“Her parents, Cynthia and Brian, [are] obviously devastated,” Villanueva told KNBC. “We’re with them. And it’s a tough day here in Santa Clarita.”

Gracie Anne Muehlberger

Muehlberger, Blackwell and three other Saugus High students were shot Thursday morning by Berhow, a junior at the school, who then shot himself in the head with a .45 semi-automatic pistol, school surveillance video showed.

Berhow remained in grave condition at Henry Mayo Newhall Hospital until his death Friday afternoon.

Of the other three survivors, whose identities are not being released by authorities, citing requests from families, one boy was treated and released from the hospital Thursday; two girls remain hospitalized at Providence Holy Cross Medical Center in fair condition and recovering, their doctors reported in a Friday morning news conference. The girls are sharing a room, and are expected to be released early next week.

“Once we were done, they were both sitting up, smiling and talking,” Dr. Boris H. Borazjani said. “They held their composure, despite being shot. And, being shot in the torso is a big deal.”

Dominic Blackwell

Sheriff’s Department Homicide detectives continue to investigate the shootings. In the midday news conference, Villanueva said Berhow had planned his attack, and knew how to handle his weapon, but that his victims were random.

“It wasn’t a spur of the moment act,” Villanueva said.

LASD Capt. Kent Wegener said there was no known motive, that no suicide note, manifesto, social media posts or any other writings by Berhow have been found.

Extensive interviews with witnesses, family, friends and classmates have yet to provide investigators with further clues.

Carlos Kenino of the Los Angeles-area Alcohol, Tobacco & Firearms bureau said all six of the firearms owned by the shooter’s late father, Mark Berhow, had been accounted for and none had been used in the shooting.

Kenino said investigators are trying to determine the origin of the .45 semi-automatic pistol Berhow used.

Two GoFundMe accounts have been set up on behalf of the Muehlberger family and Saugus High students and staff.

The city of Santa Clarita has launched its Saugus Strong website, where people can post photos and videos and leave messages of support. More than 300 visitors had posted well-wishes by 11 p.m. Friday.

The city and Saugus High alumni will also host a vigil at Central Park in Saugus on Sunday starting at 7 p.m.