The latest news from the scene is that the shooter was a woman, who was targeting her boyfriend and then committed suicide.
NBC News: Multiple law enforcement officials say that the suspected shooter at YouTube is a woman and that she is deceased. Reported w/ @anblanx— Tom Winter (@Tom_Winter) April 3, 2018
Active shooter at YouTube HQ. Heard shots and saw people running while at my desk. Now barricaded inside a room with coworkers.— Vadim Lavrusik (@Lavrusik) April 3, 2018
Whoa. Lots of cops ripping through San Bruno right now. Supposed shooting at YouTube HQ— Giancarlo Valdes (@_boogs) April 3, 2018