SANTA CLARITA (KTLA) — A student opened fire on five classmates, killing two of them, before shooting himself in the head at Saugus High School in Santa Clarita on Thursday, the day of his 16th birthday, authorities said.

The shooting, which happened at 7:38 a.m., prompted a massive response by law enforcement to the campus at 21900 Centurion Way, according to officials with the Los Angeles County Sheriff’s Department.

The first units arrived within two minutes. Deputies encountered six patients with gunshot wounds in the school’s quad, said L.A. County Sheriff Alex Villanueva.

Several students were transported to local hospitals, where two of the victims — a 16-year-old girl and a 14-year-old boy — later died, according to officials.

Neither victim has been identified.

One male student remained in critical condition at Henry Mayo Hospital, while a fourth patient, a 14-year-old boy, was hospitalized in good condition.

Two female gunshot victims, ages 14 and 15, were transported to Holy Cross Providence Hospital, according to authorities. They were reported to be in good to fair condition, said hospital spokeswoman Patricia Aidem.

The suspect was among the six wounded, according to Villanueva. He was taken to a hospital and, as of early Thursday afternoon, is listed in grave condition. Authorities said they could not confirm the suspect was the critically wounded boy being treated at Henry Mayo.

Early reports of the number of victims from the shooting ranged from four to as many as seven. The Los Angeles County Fire Department later confirmed six patients total were transported to local hospitals.

Saugus High is in a suburban area about 30 miles northwest of downtown Los Angeles.

Suspect allegedly shot 5 others, himself

The shooting triggered a massive response from deputies and a shelter-in-place order as law enforcement combed the area for the gunman.

Eventually, they realized the suspect was among the students who had been taken to local hospitals after interviewing witnesses and combing through video, one of which apparently showed the incident unfold.

“Detectives have reviewed the video at the scene, which clearly shows the subject in the quad withdraw a handgun from his backpack, shoot and wound five people and then shoot himself in the head,” sheriff’s Capt. Kent Wegener said.

Authorities have not released the name of the 16-year-old, saying only the shooting took place on his birthday.

A weapon has been recovered. Villanueva described the gun as a .45-caliber semi-automatic pistol.

Investigators have executed a search warrant at the suspect’s home in a nearby residential neighborhood, according to the Sheriff’s Department. Law enforcement vehicles could be seen throughout the day outside the residence, which is located in the 22900 block of Sycamore Creek Drive.

The suspect’s mother and girlfriend were being interviewed as detectives try to determine a motive, according to Villanueva.

The FBI is assisting with the investigation.

Undersheriff Tim Murakami said investigators are looking into rumors the alleged gunman possibly posted threats to social media prior to the shooting.

A neighbor who has known the suspect all his life told KTLA the teen’s father had died two years ago and he had been going through a tough time.

“I’ve known the whole family my whole life. It’s just, it’s so surprising. You hear about things like this in the news, you don’t expect it to be your own community,” said the neighbor, Jared.

‘We ran as fast as we could’

Students described a chaotic scene when gunfire erupted on campus before the start of classes. An 11th grader told KTLA she was outside of the library with friends when they heard five or six gunshots ring out.

“I heard a bullet hit the wall right next to where we were standing. … We ran as fast as we could,” said the student, who identified herself as Riley. “There were hundreds of us just running as far away as possible.”

Braden, a 10th grader, told KTLA the situation unfolded right after his mother dropped him off at school.

“As soon as I found out, I saw the kids running,” he said. “I knew it was serious, so I just ran back to my mom’s car.”

Frightened students barricaded themselves and hid inside their classrooms while concerned parents frantically rushed to campus.

“They’re texting us that they’re hiding in closets, they’re scared to die,” one mother said as she held her daughter, who was among the first wave of students to get off the campus.

Another parent told KTLA she received a text message from her daughter as she was preparing to head out to work.

“She told me, ‘Mom, I’m so scared. I love you guys so much. Please come, please come,’” the woman told KTLA. “That just killed me.”

Several students told KTLA that they had been doing practice drills — “even when we were little,” one said — in schools to prepare for the possibility of such an incident.

“It’s so different when it actually happens, you don’t think it ever will – you hope it won’t,” said a student who identified himself as Jacob. “I’ve been living here my whole life and never thought here it would happen. And today shows it can happen anywhere.”

Classes canceled Friday districtwide

All campuses in the William S. Hart Union High School District will be closed Friday “out of respect for the victims and their families,” Deputy Superintendent Mike Kuhlman said.

“Please join me in keeping these families in your hearts and prayers,” Kuhlman wrote in a statement. “Today’s events took the life of their children; words are utterly inadequate when we think about their loss.”

Despite canceled classes, Kuhlman said administrators wanted to allow students and staff to convene off-campus “to process their feelings with counselors, with their teachers, and with one another.”

Counselors would be available 5-7 p.m. Thursday at the Santa Clarita Activities Center, at 20880 Centre Pointe Parkway, and 8 a.m. to 4 p.m. Friday at Grace Baptist Church, 22833 Copper Hill Drive.

Earlier Thursday, all the district’s schools were on lockdown amid the search for the gunman. The lockdowns have since been lifted.

The Castaic Union School District also temporarily placed all of its campuses on lockdown as a precautionary measure.

Students would be interviewed by investigators before being released to their parents, Murakami tweeted.

Parents were told to pick up their students at Central Park at 27150 Bouquet Canyon Road.

The Department of Mental Health dispatched support teams to the campus to work with student and family members, according to Supervisor Kathryn Barger, who represents the county’s Fifth District.

“As you can imagine, the impact that this is going to have, not only on this school but on this community, is tremendous,” Barger said.

KTLA’s Nidia Becerra, Anthony Kurzweil and Kristina Bravo contributed to this story. 

Latest News Headlines: