Police believe that suspect Patrick Crusius, who just turned 21, posted a manifesto on 8chan detailing his apparent rationale and writing that he had to “do this before I lose my nerve.”
Crusius is the third accused gunman to post on 8chan in advance of a shooting.
The site has been described as a "go-to resource for violent extremists" and a "megaphone for mass shooters."
Now, even the man who founded the site is calling for it to be taken down. Fredrick Brennan founded 8chan in 2013 as a haven for free speech. He later relinquished control because he felt its content had become toxic.
In the wake of the El Paso shooting Saturday, Brennan is calling on the site's new owners to shut it down.
“Once again, a terrorist used 8chan to spread his message as he knew people would save it and spread it,” he told The Washington Post. “The board is a receptive audience for domestic terrorists.”
The site has been experiencing intermittent outrages after security company Cloudflare said it would no longer provide its services protecting the message board from denial-of-service attacks. 8chan is currently seeking another solution, the site posted on Twitter.
Crusius has been booked into jail on a charge of capital murder and has not yet entered a plea.