The attacker, who fatally shot herself in the incident after wounding three people on the video site’s Silicon Valley campus, was a prolific video blogger on YouTube and an animal rights activist.
Aghdam’s father has since told the Bay Area News Group that she was angry at YouTube because it had stopped paying her for videos she posted on the platform. People who post on YouTube can receive money from advertisements that accompany their videos, but the company “de-monetises” some channels for reasons including inappropriate material or having fewer than 1,000 subscribers.
YouTube had “stopped everything” and “she was angry,” Ismail Aghdam said in a telephone interview.
Ismail Aghdam said he reported his daughter missing on Monday after she did not answer her phone for two days.
He said the family received a call from Mountain View police around 2am on Tuesday saying they found Aghdam sleeping in a car.
He said he warned them she might be headed to YouTube because she “hated” the company.
Mountain View Police spokeswoman Katie Nelson confirmed officers located a woman by the same name asleep in a vehicle asleep in a Mountain View parking lot on Tuesday morning. Ms Nelson said the woman declined to answer further questions but would not be drawn on whether police were warned Aghdam might go to YouTube.
Ismail Aghdam said his daughter was a vegan activist and animal lover.
During the attack on YouTube, terrified employees huddled inside their offices, calling 911, as officers and federal agents swarmed the company’s suburban campus in the San Francisco Bay Area city of San Bruno.
Employee Dianna Arnspiger said she was on the building’s second floor when she heard gunshots, ran to a window and saw the shooter on a patio outside.
She said the woman wore glasses and a scarf and was using a “big huge pistol”.
“It was a woman and she was firing her gun. And I just said, ‘Shooter,’ and everybody started running,” Ms Arnspiger said.
She and others hid in a conference room for an hour while another employee repeatedly called 911 for updates.
“It was terrifying,” she said.
A 36-year-old man was in critical condition, a 32-year-old woman was in serious condition and a 27-year-old woman was in fair condition, a spokesman for San Francisco General Hospital said.
San Bruno Police Chief Ed Barberini initially said there were four people who had been shot but later clarified that a fourth person had suffered an ankle injury.
Zach Vorhies, 37, a senior software engineer at YouTube, said he was at his desk working on the second floor of one of the buildings when the fire alarm went off. He got on his skateboard and approached a courtyard, where he saw the shooter yelling, “Come at me, or come get me.”
He saw somebody lying nearby on his back with a red stain on his stomach that appeared to be from a bullet wound. Mr Vorhies said he realised there was an active shooter when a police officer with an assault rifle came through a security door.
He said the public can access the courtyard where he saw the shooter during work hours.
Michael Finney, a 21-year-old restaurant supervisor at Carl’s Jr across from the campus, said he came out of the bathroom to see a woman in a booth bleeding from the calf. Two friends were trying to stop the bleeding, using the victim’s sweatshirt as a tourniquet, but it wasn’t helping, he told The San Jose Mercury News.
“Everyone was figuring out what to do,” Mr Finney said. “I was trying to stay calm and see what I could do. Everybody is shocked.”
Google, which owns the world’s biggest online video website, said the company’s security team worked with authorities to evacuate buildings and was doing whatever it could support the victims and their families.
YouTube’s headquarters has more than a thousand engineers and other employees in several buildings.
“Today it feels like the entire community of YouTube, all of the employees, were victims of this crime,” said Chris Dale, a YouTube spokesman. “Our hearts go out to all those who suffered.”
Despite reports that Aghdam was angry at YouTube for censoring her videos, police initially said the shooting was being investigated as a domestic dispute.
Aghdam was known for her animal rights advocacy and was quoted in a 2009 story in The San Diego Union-Tribune about a protest by People for the Ethical Treatment of Animals (Peta) against the use of pigs in military trauma training. She dressed in a wig and jeans with drops of painted “blood” on them, holding a plastic sword at the demonstration outside the Camp Pendleton Marine Corps base.
“For me, animal rights equal human rights,” Aghdam told The Union-Tribune at the time.
Her website, nasimesabz.com, contains a warning that “Dictatorship exists in all countries but with different tactics!”, quotes Adolf Hitler to illustrate her point and features an attack on YouTube explicitly: “There is no equal growth opportunity on YOUTUBE or any other video sharing site, your channel will grow if they want to!!!!!”
The White House said President Donald Trump was briefed on the shooting and that officials were monitoring developments.
AP contributed to this report
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