Here's everything we know so far about the YouTube shooter
Police retraced Nasim Aghdam whereabouts hours before she carried out a shooting spree at YouTube Headquarters in San Bruno.>>She was at the gun range early the morning of the incident.>>Police say Aghdam shot three people at lunch time then took her own life.
YouTube remains closed today as investigators gather evidence.
Forensic experts are pouring over Aghdam's social media profiles for clues but they believe they have a possible motive.
It is believed that the suspect was upset with policies and practicies of YouTube.
Investigators say they know how the shooter gained access to the building.
The suspect is believed to have parked her vehicle to the rear of a neighboring business and access the campus via a parking garage.
We just have to figure out the area that she entered, what level of security existed at that point.
One victim was found at the
The building's front entrance.
The other two managed to escape to nearby restaurants.
YouTube employee Diana Arnspiger says she saw the shooter from the office's second floor.
I ran to the window because the window behind me looks over the patio, and I saw her.
And it was a woman.
And she was firing her gun.
And I just said
Shooter, and everybody started running.
The shooter's father says he warned police that she was upset with YouTube and afraid of what might happen.
Danielle Nottingham, CBS News San Bruno, California.