Oregon shooting and the anonymous '4chan' message board
In the midst of Thursday's shooting in Oregon, it emerged that posts on an online message board were playing a central role in people trying to identify the gunman.
One post in particular on the 4chan message board - which describes itself as "a simple image-based bulletin board where anyone can post comments and share images anonymously" - threatened a school shooting in the northwest of the US.
Comments made by others in the thread following this post, encouraged the original poster, 'OP', to carry out his threats.
It is not yet clear whether the anonymous comments came from the gunman himself or from another user.
Police have not identified the attacker but unnamed officers have told US media his name is Chris Harper Mercer.
The site is now being investigated by federal law enforcement authorities in the US, according to the New York Times.
The 4chan message board offers an anonymous and largely unmoderated platform for discussion. People often post threats on the site and others reply.
When a mass shooting was committed at a cinema in Aurora, Colorado in 2012, there were also suspicious threads surrounding the incident on 4chan.
One post in Thursday's thread talked of getting a "high score", a reference to some of the more notorious comments in the wake of the Aurora shooting.
The thread also included discussion about socially awkward or underachieving people, with which this particular board within 4chan most identifies.
Regulars call this the "Beta uprising" and stand opposed to alpha males and females, known as "Chads" and "Stacys", as well as what they call "normies".
Message boards were a popular forum for informal online chat before the emergence of social media platforms.
However, the presence of this discussion and its link to another high profile shooting has thrown a light on the platforms and their propensity to be used to spread violent messages.