Just 19 minutes before he went into a Walmart store in the mainly Hispanic city of El Paso and gunned down 22 people, Patrick Wood Crusius was alleged to have posted his four-page manifesto of hate on the controversial 8chan website.
The document outlined Crusius’s white supremacist beliefs and said he was planning an attack.
The notice appeared along with a letter from a college that included Crusius’s name.
This is not the first time the controversial forum has served as a platform for the violent ramblings and murder plans of rightwing extremists. Before the Christchurch Mosque and the Chabad of Poway Synagogue, California shootings earlier this year, the perpetrators posted their own manifestos on the website.
Although these attackers come across as lone wolves, many of them discussed their extremist views on 8Chan beforehand and by the time law enforcement acts, often it is too late.
Here are five things you may not know about the site:
The site is funded by a pig farmer based in the Philippines
On Tuesday, the site’s owner, Jim Watkins, was asked to testify before Congress in the wake of the El Paso shootings, but is yet to publicly respond. Earlier that day, he posted a video on YouTube defending the website as “a peacefully assembled group of people talking”.
Mr Watkins is a US army veteran, who now runs a pig farm in the Philippines. He has also made money building websites, including a pornographic site aimed at evading Japanese censorship laws.
The founder of 8chan, Fredrick Brennan, is no longer associated with the site and distances himself from it.
In an interview with Wired magazine in April, less than a month after the Christchurch mosque attacks, Mr Brennan said: "Since the time I resigned, I sometimes wonder whether creating 8chan was a good thing. I sometimes wonder about the things that I said in the past while I was being its admin.
“Sometimes I think I should have been harder on violent threats. I think maybe I should have worked much harder to improve the moderation systems.”
As well the far-right, 8chan has forums that attract the far-left
The site’s most infamous message board, known as “/pol/”, attracts far right groups, such as neo-Nazis and self-described fascists. Many of these came to 8chan after an exodus from the 4chan website following Gamergate, a controversial movement involving the video gaming community, which led to a torrent of misogynistic abuse and people in the industry losing their jobs.
8chan’s “/leftypol/” forum attracts characters from the radical left, supporters of communism, Marxism, anarchism and the board’s moderator is known for Stalinist views.
The website can’t be found on Google
It was kicked off the search engine in 2015. Users now mainly access it via the Tor browser through the deep web.
8chan was dropped from the search engine partly because it is easy to access malicious content on the site as it doesn’t require users to log in at all to post.
When he launched the site, Mr Brennan found other forums too restrictive and so chose a ‘free-for-all’ approach to promote free speech. The expansion and openness of the website saw it play host to some of the darkest characters on the internet, including extremists, paedophiles and trolls.
8chan has been reported to the FBI multiple times, but until recently, the website wasn’t seen as a threat
In April, the FBI filed a warrant to search 8chan’s Nevada office seeking information on the Chabad of Poway synagogue shooter, who had posted on the forum before the attack.
Mr Watkins said on Wednesday that he was working with the FBI “within minutes” of the three recent shootings linked to 8chan.
It has a forum dedicated to a racist plot to colonise Namibia
8chan users on that forum believe Namibia is a wild lawless space that they can colonise as white supremacists to promote alleged “values” of National Socialism.
They have been looking to raise funds towards their cause under the guise of a charity.