One person was killed and at least three others were injured in a shooting at YouTube’s headquarters in San Bruno, California, on April 3.

Police said they believe the female shooter killed herself after firing shots at several YouTube employees in the building, ABC news reported.

The attack left a 36-year-old man in a critical condition and two women, aged 32 and 27, were also seriously injured, the report said.

These videos show a SWAT team climbing up the stairs to the entrance of YouTube HQ. Credit: Eddie DiSalvo via Storyful