The shooter who injured three people at YouTube's headquarters in Northern California has been identified.
Here's what we know:
1. Unusually for a mass shooter, the suspect was a woman.
Her name was Nasim Aghdam and she was 38.
2. She was armed with a 9mm handgun and shot one man and two women, before turning the gun on herself.
One other person was also treated for a broken ankle.
3. One of the people she shot is believed to be her boyfriend.
The 36-year-old man is in critical condition. Local news station Kron4 reports that the shooting may have been the result of a domestic dispute.
YouTube employee Zack Vorhies told MSNBC that he witnessed a "verbal argument" near a courtyard at the headquarters, and heard a man yell "Do you want to shoot me?"
4. She was a YouTube user who seemed to be disgruntled about her videos being demonetised.
Aghdam's channel 'Nasime Wonder1' (which has been deleted since the attack) had more than 5000 subscribers, and her videos across multiple channels had been viewed more than one million times.
In January 2017, Aghdam posted a video in which she accused YouTube of "discriminating and filtering" her content. She said that her channel was receiving fewer views than it used to after being "filtered" by YouTube.
On her own website she posted videos of famous YouTubers complaining about their own videos making less money. She also wrote: "Make the lie big, make it simple, keep saying it and eventually they will believe it" - a quote by Adolf Hitler.
5. She was Persian.
Aghdam posted online using both English and Farsi, the official language of Iran. In the 'about' section of her 'Nasime Wonder1' YouTube channel, she called herself a "Persian Azeri female vegan bodybuilder".
6. She was an animal rights activist.
In 2009 Aghdam was interviewed by the Los Angeles Times as one of a number of activists protesting the use of pigs in military training.
She would often post images of disturbing animal abuse on social media, and described herself as "promoting healthy and humane living" on her 'Nasime Wonder1' YouTube channel.