The shooter who left three people injured after opening fire at YouTube's headquarters has been named as an animal rights activist who claimed the firm censored her.
Nasim Aghdam, who used the name Nasime Sabz on social media, began shooting at the campus near San Francisco on Tuesday, The Mirror reports.
Staff heard gunshots as they were eating their lunch, and witnesses reported hearing at least 20 bullets fired.
Aghdam was pictured at a PETA (People for the Ethical Treatment of Animals) rally in San Diego paper over the use of pigs in military training in 2009.
On her now defunct YouTube page, the 39-year-old described herself as "the Persian Azeri female vegan athlete and animal rights activist promoting VEGANISM, the healthy and humane way of living."
She appeared to bear a grudge against YouTube claiming she was not receiving money owed for her video hits.
Last February she posted a picture which appeared to show Aghdam holding a home-made protest sign which read: "Youtube dictatorship. Hidden policy: promote stupidity, discrimination, suppression of truth."
Early reports were that the shooter may have targeted a boyfriend but it is now understood Aghdam was not known by anyone at YouTube.
CBSNews said Aghdam's father Ismail told them his daughter had been missing for several days and he'd told police she was "angry" at YouTube.
He said police contacted him to say Aghdam had been found in Mountain View, where Google has its headquarters, on Monday night.
Mr Aghdam said YouTube "stopped everything and now she has no income."
Employee Dianna Arnspiger was on the second floor when she heard shots, ran to a window and saw the shooter on a patio outside.
She said the woman wore glasses and a scarf and was using a "big huge pistol."
"It was a woman and she was firing her gun,' Dianna told Kron4news.
"And I just said 'Shooter!' and everybody started running."
Police said early investigations indicated the shooting was of a domestic nature and not terrorism-related.
SWAT teams rushed to the scene within minutes of receiving the first emergency calls at around 12.46pm.
They first found a man with gunshot wounds who was transported to hospital.
The woman shooter was then found dead from what appears to be a self-inflicted gunshot wound.
Pictures later emerged showing a body, covered with yellow tarpaulin, near to a shattered door.
Two more victims were later found as police searched the building and were also taken to hospital with gunshot wounds.
Chief Ed Barberini said the scene was "very chaotic".
He said they were "hopeful" that all those injured will survive.
A spokesman for San Francisco General Hospital later said of the three patients; a 36-year-old man is in a "critical" condition, a 32-year-old man is "serious" and a 27-year-old woman is described as "fair".
Witnesses claimed the shooter was a white, adult female wearing a dark top and head scarf, according to ABC7 News .
Workers at YouTube, owned by Google's Alphabet Inc, said the incident appeared to have begun outside near a cafeteria.
They told of meetings suddenly coming to a stop as staff saw colleagues running towards emergency exits of the building which houses around 1,700 emloyees.
Television images showed staff walking in lines with their hands above their heads as armed police surrounded the scene.
Product manager Todd Sherman told of seeing "blood on the stairs" as he fled the building.
He wrote: "We were sitting in a meeting and then we heard people running because it was rumbling the floor. First thought was earthquake.
"After exiting the room we still didn’t know what was going on but more people were running. Seemed serious and not like a drill.
"We headed towards the exit and then saw more people and someone said that there was a person with a gun.
"At that point every new person I saw was a potential shooter. Someone else said that the person shot out the back doors and then shot themselves.
"I looked down and saw blood drips on the floor and stairs. Peaked around for threats and then we headed downstairs and out the front.
"Police cruisers pull up, hopped out with rifles ready and I told them where the situation was as I headed down the street to meet up with a couple team members."
Google said in a statement it is working with authorities to "ensure the safety of employees".
"We continue to actively coordinate with local authorities and hospitals. Our Security team has been working closely with authorities to evacuate the buildings and ensure the safety of employees in the area.
'We have advised those who are currently at the SBO office to continue to shelter in place until further notice.
"We advised all other employees in the Bay Area, and people with meetings scheduled, to stay away from the area, and that there is no need to take any action.
"We have provided employees a helpline."
One employee at a nearby fast food restaurant told Fox New he treated a young woman who suffered a gunshot wound to the leg and had to fashion a tourniquet from a bungee cord as they waited for first responders.
