The gunwoman apparently was at YouTube the day before the shooting. Police say Nasim Aghdam visited the campus on the afternoon of Monday, April 2.
TIMELINE: Nasim Aghdam's movements leading up to YouTube HQ shooting
She was there for about 10 minutes, talking to employees, asking for directions and inquiring about a job.
Roughly 24 hours later she returned armed with a 9mm gun. She walked through the parking garage onto YouTube's campus. When an employee asked her for ID, she pulled a pistol from her purse and began firing into a crowd of workers who were sitting outside, eating lunch. She wounded three people, before she shot and killed herself.
RELATED: What we know about Nasim Aghdam
Police believe she acted alone and that she targeted YouTube because she was upset about their policy changes, including stricter requirements for video producers to make money from views of their videos.
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FULL VIDEO: Body cam footage of Mountain View police encounter with YouTube shooter