A woman who had voiced complaints online about YouTube opened fire with a handgun at the tech company's headquarters near San Francisco on Tuesday, wounding three people before shooting herself dead, authorities and media said.
It was the latest in a string of mass shootings in the United States in recent years. Most recently, the massacre of 17 people at a Florida high school has led to calls for tighter curbs on gun ownership.
Police did not identify the suspect or say what might have motivated Tuesday's shooting at YouTube, a video-sharing service owned by Alphabet Inc's Google which employs nearly 2,000 people at the San Bruno, California offices.
The woman approached an outdoor patio and dining courtyard on the campus around lunchtime and began to fire before entering the building, police said.
An affiliate of ABC and other local media, citing unnamed sources, identified the woman as Nasim Aghdam.
San Bruno police officials could not immediately be reached for comment on the identity of the attacker.
YouTube spokeswoman Jessica Mason could not immediately be reached for comment on the identification by media.
The website NasimeSabz.com, which media said was linked to the attacker, had several posts about Persian culture and veganism, interspersed with screeds against YouTube.
Those complaints included claims the company was not sharing enough revenue with people who create videos for the platform.
"There is no equal growth opportunity on YouTube, or any other video-sharing site, your channel will grow if they want to," read one posting on the site.
A YouTube account in the name of Nasime Sabz was deleted on Tuesday evening.
A US government security official told Reuters there was no known connection to terrorism.