“YouTube filtered my channels to keep them from getting views!” she wrote on the site, which includes videos promoting veganism and photos of a woman in an array of outfits, including long gowns and a camouflage unitard. She speaks in Persian and Turkish.

“There is no equal growth opportunity on YOUTUBE or any other video sharing site, your channel will grow if they want to!!!!!”

The eruption of gun violence Tuesday in Silicon Valley hit a nation still reeling from recent mass shootings and gripped by a tense gun control debate.

“This is a terrible day in the United States, when once again we have a multiple-casualty situation,” said Dr Andre Campbell, a trauma surgeon at Zuckerberg San Francisco General Hospital, which is treating victims.

The shooting left a 36-year-old man in a critical condition, a 32-year-old woman with serious injuries and a 27-year-old woman in a fair condition. A fourth person suffered an ankle injury while fleeing.

Law enforcement sources said they initially believed the shooting was a domestic incident, but are now focusing on the alleged shooter’s grudge against YouTube.

The YouTube account tied to the website was shut down “due to multiple or severe violations” of the company’s policies against spam, deceptive practices and misleading content. But it’s unclear exactly when.

The website investigators are probing videos entitled “Nasime Sabz”, which in Persian translates to “Nasim the green”

YouTube videos created by an account of the same name can no longer be viewed, but the site also features videos from other sources criticising YouTube’s policies, as well as clips promoting animal rights and veganism. Instagram and Facebook accounts listed on the website were deactivated Tuesday.

Aghdam was quoted in the Los Angeles Times in 2009, speaking at an animal rights protest outside Camp Pendleton.

“For me animal rights equals human rights,” said Aghdam, who at the time worked as a construction company office manager. 

“Just because they can’t talk doesn’t mean we should take advantage of them.”

About two weeks ago, Aghdam vented to her family that YouTube stopped compensating her for her videos, her father said.

Ismail Aghdam said that the family had called police to report his daughter missing on Monday because she hadn’t answered her phone for two days. He said he had told police she might be going to YouTube because she “hated” the company.

YouTube had “stopped everything,” and “she was angry,” he said.

YouTube’s headquarters has more than a thousand engineers and other employees in several buildings. Originally built in the late 1990s for the clothing retailer Gap, the campus south of San Francisco is known for its sloped green roof of native grasses.

Inside, Google famously outfitted the office several years ago with a three-lane red slide for workers to zoom from one storey to another.

“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.”

The White House said US President Donald Trump was briefed on the shooting and that officials were monitoring developments.

Additional reporting by Associated Press