Police say the three people who were shot at YouTube's headquarters in California were not specifically targeted.
San Bruno police said in a statement that 39-year-old Nasim Najafi Aghdam did not know the victims when she opened fire Tuesday afternoon before she killed herself.
The NBC affiliate in the Bay Area reports that Aghdam "had a robust presence on YouTube" and in a January 2017 video accused the video-sharing service of discriminating and filtering her content.
A law enforcement official said investigators believe Aghdam used the name Nasime Sabz online and had a long-running dispute with YouTube.
A website in that name decried YouTube's policies and said that YouTube was trying to "suppress" content creators.
Her father, Ismail Aghdam, told the Bay Area News Group that she "hated" the company.
Earlier Tuesday, law enforcement said the shooting was being investigated as a domestic dispute but did not elaborate. It was not immediately clear why police later said the people shot were not targeted.
San Bruno Police Chief Ed Barberini said that the shooter died of self-inflicted wounds and had used a handgun.
After receiving multiple 911 calls reporting gunfire, officers and federal agents swarmed the company's suburban campus sandwiched between two interstates in the San Francisco Bay Area city of San Bruno.
YouTube employee Dianna Arnspiger said she was on the building's second floor when she heard gun shots, 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," Arnspiger said.
She and others hid in a conference room for an hour while a male employee repeatedly called 911 for updates.
"It was terrifying," she said.
Television news footage showed people leaving the building in a line, holding their arms in the air. Officers patted them down to make sure none had weapons.
Officers discovered one victim with a gunshot wound when they arrived and then found the shooter with what appeared to be a self-inflicted gunshot wound several minutes later, Barberini said.
He said two additional gunshot victims were later located at an adjacent business and that a fourth injured person suffered an ankle injury.
The 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 several years ago famously outfitted the office with a 3-lane red slide for workers to zoom from one story to another.
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 on the campus 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.'"
There was somebody lying nearby on his back with a red stain on his stomach that appeared to be from a bullet wound.
He said he realized it was an active shooter incident when a police officer with an assault rifle came through a security door. He jumped on his skateboard and ran away.
San Francisco General Hospital received three patients: a 36-year-old man in critical condition, a 32-year-old woman in serious condition and a 27-year-old woman in fair condition, a spokesman said.
The hospital said later that it did not expect to receive more patients.
Google, which owns the world's biggest online video website, posted on Twitter that the company was coordinating with authorities. The Bureau of Alcohol, Tobacco, Firearms and Explosives said it also responded.
The White House said President Donald Trump was briefed on a shooting and that officials were monitoring developments.
A look at other workplace shootings:
- Feb 1, 2018: A former trucking company employee, Vernest Griffin, faced first-degree murder charges after two fatal shootings at separate Detroit-area businesses. Griffin was wounded and arrested following a shootout with police.
- June 14, 2017: UPS employee Jimmy Lam, who had recently filed a grievance, opened fire inside one of the company's San Francisco packing facilities, killing three co-workers before fatally shooting himself as employees fled frantically into the streets.
- June 5, 2017: John Robert Neumann Jr. fatally shot five former colleagues and then himself at a manufacturer of awnings in Orlando, Florida. Neumann had been fired from the Fiamma factory in April.
- Oct. 25, 2016: One worker was fatally shot and three others were wounded after a former co-worker opened fire in the paint shop at the FreightCar America facility in Roanoke, Virginia. The shooter, Getachew Fekede, then killed himself.
- Feb 2016: Fifteen people at a Kansas factory were shot and three of them killed by a co-worker whom police said had also shot two other people as he drove toward the facility. The shooting occurred at Excel Industries in Hesston, Kansas.
- Dec 2, 2015: A husband and wife carried out an attack on his co-workers with high-powered rifles at a health department training event and holiday party at the Inland Regional Center in San Bernardino, California. Syed Rizwan Farook and his wife Tashfeen Malik killed 14 people and wounded 22 others. Both fled the scene but then died in a shootout with police.
This story has been updated.