People who knew the 16-year-old boy suspected of killing two students in a shooting rampage at a Californian high school described him as a quiet, smart kid they never expected to turn violent.
The attacker shot five students, seemingly at random, and then shot himself in the head around 7:30 am Thursday, his 16th birthday.
Two students died, and the gunman was gravely wounded.
"I'm saddened to report that we have confirmed a total of two fatalities this morning. One female and one male," tweeted Los Angeles County Sheriff Alex Villanueva.
Three other students were wounded before the suspect shot himself in the head. He is described in US media as being in a "grave" condition.
Police and ambulances swarmed the area around the school after the early morning shooting sent panicked children running from the area.
Police have not publicly identified the shooter because he's a minor.
"Update regarding the shooting at #SaugusHigh, suspect is in custody and being treated at a local hospital," tweeted Los Angeles Country Sheriff Alex Villanueva.
The boy lived with his mother in a modest home on a leafy street in Santa Clarita, a Los Angeles suburb of about 210,000 people known for good schools, safe streets and relatively affordable housing.
His father died two years ago. Two years before that, the father had been arrested amid a domestic dispute with the boy's mother.
Brooke Risley, a Saugus High student, said she had known the boy since elementary school and sometimes studied with him on engineering projects.
Ms Risley described the boy as somewhat introverted, though open with his close friends, and "naturally smart." She said he wasn't bullied, had a girlfriend and had been an active member of a local Boy Scout troop.
"A quiet, to-himself kid," said Ryan McCracken, a 20-year-old next-door neighbour. When Mr McCracken was younger, he said they played together, sometimes in the boy's backyard treehouse.
"You wouldn't expect anything like that from him."
Joe Fitzpatrick, a senior who helped in the boy's physics class, called him a "good, quiet kid" who didn't miss assignments and did well on tests.
"He just seemed like one of those regular kids," he said.
Police said they had yet to determine a motive and any relationship between the gunman and the victims. Authorities said they have no indication the boy was acting on behalf of any group or ideology.
They confirmed a message - "Saugus, have fun at school tomorrow" - was posted to the Instagram account believed to belong to the suspect before the shooting.
According to Los Angeles County Sheriff's Department records published in a local newspaper, his father was arrested in June 2015 on suspicion of attempted battery on his wife. It's unclear how the case was resolved.
'Always been worried'
Aerial video from the local NBC affiliate showed students with hands raised being escorted by officers from the building, and led to a nearby church, as others stood outside the perimeter on their cell phones.
Denzel Abesamis, a student at the school, told the Los Angeles Times he was arriving at campus when he saw classmates fleeing the scene.
He called a friend who was hiding in a classroom with five other students.
"I've always been worried about something like this would happen since it was my actual school," he said, adding that the school had been locked down due to reports of a threat a few years earlier.
"Saugus has emphasised the importance of making sure to always be cautious of anything that may happen like an active shooter," he said.
Students are escorted out of Saugus High School. Source: AP
At least three ambulances were at the school campus, opposite a residential area, along with dozens of squad cars.
Agents from the federal Bureau of Alcohol, Tobacco, Firearms and Explosives were among those responding.
The Santa Clarita Valley Sheriff's department had warned residents to stay clear of the area.
California Senator Kamala Harris, a Democratic candidate for the 2020 election, said she was "heartbroken and praying for Santa Clarita."
"Our children and communities are being terrorised. We can't accept this," she tweeted.
