Police in California have named a woman who opened fire at YouTube’s headquarters in a suburb of San Francisco, injuring three, before killing herself.

Officials from the San Bruno police department identified her as Nasim Najafi Aghdam, who was in her late 30s.

Police said the motivation was unclear, but her father, Ismail Aghdam, told the Bay Area News Group from his San Diego home that she was furious with YouTube because it had stopped paying her for videos she posted on the platform.

Nasim Najafi Aghdam’s online profile shows she was a vegan activist who ran a website called NasimeSabz.com, meaning “Green Breeze” in Persian, where she posted about Persian culture and veganism, as well as long passages critical of YouTube.

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 at about 2am on Tuesday saying they had found her sleeping in a car.

He said he warned them she might be heading to YouTube because she “hated” the company.

A Mountain View police spokeswoman, Katie Nelson, told Associated Press that officers located a woman by the same name asleep in a vehicle in a Mountain View parking lot on Tuesday morning. Nelson said the woman declined to answer further questions but the police spokeswoman did not respond to a question about whether police were warned Aghdam might go to YouTube.

Authorities said earlier on Tuesday that the shooting was being investigated as a domestic dispute but in a statement later San Bruno police said “there is no evidence that the shooter knew the victims of this shooting or that individuals were specifically targeted”.

A spokesman for San Francisco General hospital said a 36-year-old man was in critical condition, a 32-year-old woman was in a serious condition and a 27-year-old woman was in a fair condition.

A female shooter is a rarity: an FBI study of 160 “active shooter” incidents between 2000 and 2013 found only six incidents, or 3.8%, were perpetrated by a female shooter.

News of Tuesday’s shooting initially spread on social media as YouTube employees posted about barricading themselves inside rooms as police and ambulances arrived at the scene.

“Heard shots and saw people running while at my desk. Now barricaded inside a room with coworkers,” tweeted Vadim Lavrusik, a YouTube employee.

Another YouTube employee, Michael Ho, said he was on the phone with his wife in an open-plan area when he saw people running. “At first I wasn’t sure if it was something they were doing for fun,” he said, before noticing looks of panic on people’s faces.

Aerial footage shot by CBS News showed staff leaving the building with their hands in the air. Offices of other companies nearby were also on lockdown.

Sundar Pichai, the chief executive of Google, YouTube’s parent company, said in an email to staff the shooting was an “unimaginable tragedy” and that the company was working to support the victims and their families.

Aghdam’s social media posts highlighted pro-vegan views and criticised animal cruelty. She was also quoted in a 2009 story in the San Diego Union-Tribune about a protest by People for the Ethical Treatment of Animals against the use of pigs in military trauma training. “For me, animal rights equal human rights,” Aghdam told the Union-Tribune at the time.

YouTube terminated Aghdam’s account following the shooting. Her Instagram and Facebook accounts have also been removed.

A screenshot of a video posted on Aghnam’s YouTube channel before it was taken down showed her complaining that “YouTube filtered my channels to keep them from getting views.”

Associated Press and Reuters contributed to this report