A woman shot at least four suspects before killing herself at the headquarters of YouTube south of San Francisco, witnesses and police say.
Witnesses said the woman wounded at least four people before taking her own life about 1pm (6am AEST) local time at the office complex in San Bruno, California.
“It was very chaotic, as you imagine,” San Bruno Police Chief told a press conference.
“We did encounter one victim with an apparent gunshot wound towards the front of the business as we arrived. A 37-year-old man is in a critical condition.
“Several minutes later while conducting a search of the premises, officers located a second individual with a gunshot wound that may have been self-inflicted.”Stanford Hospital also confirmed taking in four or five patients injured in the shooting.  It is not confirmed whether thsy were shot or injured another way.