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

The suspect in Saturday’s mass shooting at a Pittsburgh synagogue is a 46-year-old local man named Robert Bowers who posted virulent antisemitic messages on social media filled with slurs and conspiracy theories.

Two hours before a gunman burst into the Tree of Life synagogue and opened fire during a Shabbat religious service, Bowers posted on chat site Gab.com about the Hebrew Immigrant Aid Society (HIAS), a non-profit that helps Jewish refugees relocate to the United States.

“HIAS likes to bring invaders in that kill our people. I can’t sit by and watch my people get slaughtered. Screw your optics, I’m going in,” wrote Bowers, a heavy-set, white male.

The gunman reportedly shouted antisemitic phrases during the shooting, which left 11 people dead and five injured, including four police officers.

The suspect, a Pittsburgh resident, was shot and in fair condition at a hospital, authorities said.

Gab.com said in a statement that when it learned of the shooting suspect’s profile on its site, it took “swift and proactive” action to contact law enforcement immediately.

Gab, which promotes itself as a free-speech alternative to the more heavily policed Twitter and has been a popular gathering space for the alt-right, said it backed up the user data and suspended the account, then told the Federal Bureau of Investigation about the data held by the company.

“Gab unequivocally disavows and condemns all acts of terrorism and violence,” the company’s statement said.

Bower has an active firearms license and has made at least six known gun purchases since 1996, a law enforcement official familiar with the investigation told CNN. He did not have a criminal record and was not known to police, law enforcement officials said on Saturday.

An archive of Bower’s Gab posts since he joined the site in January showed an angry, antisemitic man who shared messages such as: “Daily Reminder: Diversity means chasing down the last white person.”

About a month ago he posted pictures showing what appeared to the results of his target practice at a shooting range, and a collection of three handguns that he called his “glock family.”

Police said the suspect had three handguns and an assault-style rife at the shooting. It’s unclear whether they were the same handguns as the ones in the photo.

Bowers, who is a registered voter with “no affiliation” in Allegheny County, Pennsylvania, took aim in one post at US President Donald Trump, accusing him of being a “globalist” who did nothing to stop the “infestation” of the United States by Jews.

“For the record, I did not vote for him nor have I owned, worn or even touched a MAGA hat,” he wrote. MAGA is an acronym for Make America Great Again that is frequently used by Trump.