The suspected Pittsburgh shooter allegedly had a following on a social network that many call the far-right's alternative to Twitter — here's everything we know about Gab

SWAT police officers respond after a gunman opened fire at the Tree of Life synagogue in Pittsburgh, Pennsylvania, U.S., October 27, 2018.

The man who allegedly opened fire in a Pittsburgh synagogue Saturday morning, killing 11 people and injuring six, was reportedly a frequent poster on Gab, a relatively new social network that has attracted many from the far-right fringe.

Robert Bowers, the suspected shooter, reportedly joined Gab at the beginning of this year, using it to post a series of anti-Semitic messages and redistribute many more from other users. Immediately before he allegedly attacked the synagogue, Bowers took aim at HIAS, a Jewish organization that helps refugees.

"HIAS likes to bring invaders in that kill our people," he wrote, according to an archive of his Gab posts. "I can't sit by and watch my people get slaughtered. Screw your optics, I'm going in.

Gab, which bills itself as the free-speech alternative to Facebook and Twitter, has become a haven for far-right extremists. The site does not police hate speech, instead encouraging users to take advantage of its tools to filter out posts they find offensive.

Here's what we know about Gab:

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Gab was launched in August 2016.

Initially, consumers could only use the site if they'd been invited to register.

The site was cofounded by Andrew Torba.

Torba previously cofounded AutomateAds.com, previously known as Kuhcoon, a social media advertising company that had been backed by Y Combinator. Rival AdHawk purchased AutomateAds last year.

Torba founded Gab with Ekrem Büyükkaya, with whom he'd worked at AutomateAds.com.

Torba launched Gab as an alternative to Facebook and Twitter.

Torba told BuzzFeed News he had been frustrated with the way "left leaning Big Social" sites were filtering posts, feeling like they weren't qualified to judge what was news or harassment.

"It didn't feel right to me, and I wanted to change it, and give people something that would be fair and just," he told BuzzFeed News.

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