On April 3, 2018, at approximately 12:46 p.m. PDT, a shooting occurred at the headquarters of the American video-sharing website YouTube in San Bruno, California.

The shooter was identified as 38-year-old Nasim Najafi Aghdam, an Iranian-American woman, who entered through an exterior parking garage, approached an outdoor patio, and opened fire with a Smith & Wesson 9 mm semi-automatic pistol.

[21] She lived with her grandmother in Riverside County, California,[17][18] and posted content on Facebook, Instagram, Telegram and YouTube in Persian, Azerbaijani, English and Turkish.

[22] She had protested with People for the Ethical Treatment of Animals (PETA) against the use of pigs in United States Marine Corps' training procedures for victims of trauma.

[25][26] The morning before the shooting, police officers found Aghdam sleeping in her car in a Walmart parking lot in Mountain View, 23 miles (37 km) south of YouTube's headquarters.

[34] Her father Ismail, of Riverside County, said that his daughter was a "vegan activist and animal lover" who told him that YouTube had been censoring her videos and stopped paying her for her content.

"[41] Other politicians who extended condolences included Vice President Mike Pence, Minority Leader of the United States House of Representatives Nancy Pelosi, and California U.S. senator Dianne Feinstein.

"[45] Google CEO Sundar Pichai echoed his sentiments on Twitter, and sent an email to his employees describing the shooting as an "unimaginable tragedy" and a "horrific act of violence.