Police have described the chaos inside the building and finding the injured with gunshot-related wounds.
A woman with a gun opened fire today (NZT) at the headquarters of YouTube, shooting three other people before turning the weapon on herself, officials said.
The violence began about 12.45pm in a courtyard outside the company's headquarters, south of San Francisco. Witnesses described seeing a woman shooting a gun in a courtyard as others ran for their lives.
"Upon arrival, officers encountered numerous employees fleeing from the building," said San Bruno Police Chief Ed Barberini. "It was very chaotic, as you can imagine."
Police in San Bruno were quick to respond to the incident, which left one person - alleged to be the shooter - dead. Photo / AP
Police found one gunshot victim near the entrance of the building, he said.
Two injured women ran across the street and sheltered in a restaurant, officials said. As police investigators searched the building, officials said a fourth person was injured, but it was unclear what those injuries were, or where that person was taken for treatment.
One of the injured women had a bullet wound in her leg. A worker told KTVU that he fashioned a bungee cord into a tourniquet, helping the woman until she was taken to an area hospital.
The shooter was not immediately identified, nor were the victims.
San Francisco General Hospital said a 36-year-old man was in critical condition, and two other women were being treated for injuries. One of the women was in critical condition, and the other was in fair condition, a hospital official said.
— Google Communications (@Google_Comms) April 3, 2018
Employees described a chaotic scene inside the corporate offices when the gunshots rang out. Some fled while others hid.
Vadim Lavrusik, who works on the company's product team, tweeted that he heard shots and saw people running.
"Now barricaded inside a room with co-workers," he wrote at about 1pm local time.
Armed law enforcement personnel leave YouTube headquarters. A woman opened fire at the offices setting off a panic among employees. Photo / AP
Todd Sherman, a product manager at the company, described the frightful moments as he evacuated the building.
"I looked down and saw blood drips on the floor and stairs," he wrote on Twitter.
Dozens of officers converged on the building and conducted a room-to-room search for any attackers. Many YouTube workers were escorted out of the building with their hands in the air, as police worked to secure the large office space.
Was just briefed on the shooting at YouTube’s HQ in San Bruno, California. Our thoughts and prayers are with everybody involved. Thank you to our phenomenal Law Enforcement Officers and First Responders that are currently on the scene.
US President Donald Trump praised the quick response: "Our thoughts and prayers are with everybody involved. Thank you to our phenomenal Law Enforcement Officers and First Responders that are currently on the scene."
Most acts of mass violence are done by men, and female shooters are rare. An FBI report of active shootings nationwide between 2000 and 2013 examined 160 such attacks and found that just six involved female shooters.
The bestl-known mass shooting in recent memory involving a female attacker was in 2015 in San Bernardino, California, about 700km southeast of YouTube's offices. A husband and wife who had pledged allegiance to the Islamic State gunned down 14 people at an office holiday party before they fled and were killed by police.
