A suspected lone shooter is dead following reports of gunfire Tuesday afternoon at the YouTube headquarters in San Bruno, California.
The suspected female shooter appears to have died from a self-inflicted gunshot wound, San Bruno Police Chief Ed Barberini said during a news conference. Four others were injured, officials said. One appeared to have injured an ankle while fleeing, while the other three sustained gunshot wounds.
Barberini confirmed to reporters Tuesday that the weapon used was a handgun, but he would not release the name of the suspect or give any information on possible motives.
Law enforcement officials received numerous 911 calls around 12:45 p.m. local time regarding gunshots at the YouTube offices, according to Barberini. Upon arrival, officers discovered a "very chaotic" scene as numerous employees fled the building, he said.
"One person had a gunshot wound as we arrived," Barberini said. "Several minutes later, while conducting a search of the premises, officers encountered a second individual with a gunshot wound that may have been self-inflicted. We are still working on confirming that. Two additional victims were located several minutes later at an adjacent business."
The active shooter situation had been resolved by 2:20 p.m. local time, San Bruno City Manager Connie Jackson told HuffPost. "The situation is safe although the public has been asked to stay away," she said.
Sundar Pichai, the CEO of Google, which owns YouTube, released a statement Tuesday to employees, thanking first responders and the company's security team for their quick actions that helped to keep people safe.
"I know a lot of you are in shock right now," Pichai's statement said. "Over the coming days, we will continue to provide support to help everyone in our Google family heal from this unimaginable tragedy."
A spokesman for San Francisco General Hospital said at a news conference that it received three patients: a 32-year-old female in serious condition, a 27-year-old female in fair condition and one 36-year-old male in critical condition.
Dr. Andre Cambpell, a trauma surgeon at San Francisco General, said at a later conference that all the patients were awake and aware of what happened. Campbell also said that he didn't expect any of the patients to require surgery.
"Once again we are confronted with the specter of a mass casualty situation in the city of San Francisco, where we now have three victims that we have taken care of," Campbell said. "This is unfortunate and continues. To think that after we've seen Las Vegas, Parkland, the Pulse nightclub shooting, that we would see an end to this, but we have not. "
According to Lisa Kim of Stanford Health Care, the hospital didn't treat any victims of Tuesday's shooting at YouTube. A Stanford spokesperson previously told HuffPost the hospital was treating four to five patients but later corrected that statement.
Graeme MacDonald, a 41-year-old product manager for Walmart eCommerce, watched the scene unfold from the fifth floor of his office building, roughly 1,000 feet away from the YouTube HQ.
"I had come back from lunch and there were a couple people running in to get on the elevators," MacDonald told HuffPost. "They were visibly shaken. They had heard gunshots."
MacDonald said he saw an estimated 20 people evacuate YouTube with their hands over their heads around 1 p.m. local time.
"They looked scared," he said. "There are helicopters are going by overhead. Evacuees were brought over behind our building. They've been telling us to stay away from the windows. ... It's Silicon Valley. It's a high-stress sort of area, but it still shocks me because there's not a gun culture here at all."
Vadim Lavrusik, a product manager for YouTube Live, and Dan Afergan, a software engineer for the company, both tweeted about the shooting on their campus.
Lavrusik said he heard shots and was barricaded inside of a room with his co-workers. Less than 20 minutes later, Lavrusik said he had been safely evacuated from the building.
Google said it was coordinating with authorities in response to the situation. There are about 1,700 people who work in the YouTube office, according to ABC 7 San Francisco.
Security at the Google office in Mountain View, California, 30 minutes south of YouTube's headquarters, is typically strict. Employees who bring in guests are required to sign them in before entering the building.
At YouTube's San Bruno office, people can freely enter the reception area, but need to be signed in before entering employee areas.
In a series of tweets, Todd Sherman, a product manager for YouTube, said he was in a meeting when the heard people running in the offices.
He said he first thought it was an earthquake, then he saw more people running.
"We headed towards the exit and then saw more people and someone said that there was a person with a gun," Sherman wrote.
"At that point, every new person I saw was a potential shooter," he added. "Someone else said that the person shot out the back doors and then shot themselves."
While heading toward the building's exit, Sherman said he saw "blood drips on the floor and stairs."
Outside, Sherman said, police officers had hopped out of their cruisers with rifles ready.
"I told them where the situation was as I headed down the street to meet up with a couple team members."
Rep. Jackie Speier (D-Calif.), whose district includes the YouTube headquarters, said she was "shocked and saddened to hear about another mass shooting."
"We must take action and #EndGunViolence," she tweeted.
President Donald Trump tweeted his "thoughts and prayers" to everyone involved.
This story is developing. Check back for updates.
With files from Doha Madani