https://www.theverge.com/2018/4/4/17197100/youtube-headquarters-shooting-shooter-motive-hoaxes

Yesterday, a shooter walked into YouTube’s headquarters in California and began firing at employees, leaving three people injured with gunshot wounds. A picture of the tragedy, and the suspect behind it, is now emerging. Here are the facts that have come to light so far.

Around lunchtime on Tuesday, April 3rd, employees at YouTube’s headquarters in San Bruno, California, began reporting gunshots fired in the building. Several employees called 911, and others tweeted about the shooting, including Vadim Lavrusik, whose message was widely cited in early reports.