Updated Wednesday at 9:05 a.m.
Two of the shooting victims at YouTube headquarters in San Bruno were released from San Francisco General Hospital Tuesday night. A 36-year-old male remains in serious condition.
A woman believed to be the shooter at YouTube headquarters in San Bruno has died from an apparent self-inflicted gunshot wound, and three others have been wounded, San Bruno Police Chief Ed Barberini said Tuesday.
San Francisco General Hospital says it has received three patients: A 36-year-old man is in critical condition, a 32-year-old woman is in serious condition, and a 27-year-old woman is in fair condition, according to SFGH spokesman Brent Andrew.
A fourth victim, also hospitalized, suffered a lower leg injury while fleeing the building, Barberini said.
Initial reports of gunfire at the YouTube building came in at 12:46 p.m. Tuesday afternoon. Early on, police in San Bruno said there was an active shooter but could not provide more information. Multiple 911 calls reported gunfire, and police and fire officials responded, according to City Manager Connie Jackson. According to Barberini, San Bruno police officers arrived at the scene two minutes after initial calls, at 12:48 p.m.
San Bruno police had called for people to stay away from the area surrounding Cherry Avenue and Bayhill Drive.
In the hours immediately after the shooting, Chief Barberini said that authorities were clearing and searching buildings for other possible shooters "in a "slow methodical manner," but he said there was no additional information to suggest anyone else was involved.
By 5 p.m, the active situation had transitioned "into a static, investigative effort," Barberini said, but so far "we know very, very little" about the shooter.
Barberini confirmed that the weapon used in the shooting was a handgun.
Television news footage showed people leaving the building in a line, holding their arms in the air for police to inspect as they were coming out. Officers patted down people grouped outside, and police vehicles surrounded the area.
Google, which owns the world's biggest online video website, posted on Twitter that the company was coordinating with authorities. The company said its security team had been working with authorities to evacuate buildings on campus following the shooting.
Later Tuesday, Google CEO Sundar Pichai issued the following statement "to Googlers worldwide":
The San Francisco Field Division of the Bureau of Alcohol, Tobacco, Firearms and Explosives also responded to the shooting at YouTube's suburban campus.
Zach Vorhies, a senior YouTube software engineer, described events after a fire alarm was sounded.
“I was programming when the fire alarm was pulled," Vorhees said. "I went outside with my electric skateboard and I started skating down because I thought it was a fire. I heard some yelling and I saw somebody down on his back with a red spot on his stomach and somebody was yelling, ‘Come get me.’ Then I saw a police officer entering through the gate with an assault rifle, and then I turned around and I ran away. And then I escaped through the parking structure and came out, and here I am.”
YouTube employee Vadim Lavrusik posted on Twitter that he heard gunshots and saw people running. He said he was barricaded in a room with his co-workers before being safely evacuated.
Will Hudson said his friend who works for YouTube texted him about the shooter.
"I think there might be a shooter in my building," read one text. "The fire alarm went off so we started to evacuate and then people (started) running saying there was a shooter."
Hudson said his friend has made it safely back to San Francisco and is in contact with his family. Hudson said he has become accustomed to hearing about such violence but has never been so close to it before.
"It just feels strange. It feels like it could really be anyone. That's really the strangeness of it," he said.
The White House says President Trump has been briefed on the shooting and that officials are monitoring it.
This story has been corrected to remove a reference that patients were taken to Stanford Hospital because the hospital now says it gave incorrect information about receiving patients from the shooting.
KQED's Don Clyde, Monica Samoyoa, Adam Grossberg and the Associated Press contributed to this report.