(CNN) -- The woman who opened fire at YouTube headquarters in Northern California may have been a disgruntled user of the video-sharing site.

Police identified the woman in Tuesday's shooting as San Diego resident Nasim Najafi Aghdam, who was in her late 30s.

Aghdam wounded three people at the campus in San Bruno, south of San Francisco, then turned the gun on herself, authorities said. A fourth person suffered an ankle injury while escaping the gunfire.

    Authorities don't know of a motive for the shooting, but they are investigating a website that appears to show the same woman accusing YouTube of restricting her videos, according to the Los Angeles Times.

    A spokesman for Zuckerberg San Francisco General Hospital, a level 1 trauma center, said the facility received three patients. One 36-year-old man was in critical condition, one 32-year-old woman was in serious condition and one 27-year-old woman was in fair condition.

    One YouTube employee said during the shooting people were trying to get out of the building "as fast as they could."

    She said she was on a conference call and her boss, who heard shots, told her at least one person was shot on the patio where people eat.

    "We were all suddenly aware of a lot of noises, of sounds, people running outside of the room where she was. And people screaming," said the employee, who was in a building down the street.

    "I have to get out of here," the woman said her boss said.

    A witness told CNN affiliate KRON he heard two or three shots and later about 10 shots. He was at a Carl's Jr. fast-food restaurant across the street from an end of the YouTube building where there are tables with umbrellas on a patio.

    A woman ran over to the Carl's Jr. with a leg wound, he said. People at the fast-food restaurant tried to use napkins to stop the bleeding.

    Overhead video from KGO showed a heavy police presence outside the YouTube building. A crowd of people gathered outside the building and, one by one, were frisked and patted down by officers. Several roadways near the building were closed to traffic.

    YouTube, which was founded in February 2005, quickly became the most well-known of several online video sites. In 2006 Google said it was purchasing YouTube for $1.65 billion in stock.

    More than 1,100 people work at the YouTube office in San Bruno. Employees there include engineers working on site search, infrastructure, content channels and ad products; and sales teams that work with advertisers and content creators.

    The Bureau of Alcohol, Tobacco, Firearms and Explosives and FBI will help investigate the incident, according to the angencies' San Francisco offices.

    San Bruno is about 13 miles south of San Francisco.

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