The man accused of murdering at least 11 people at a Pittsburgh synagogue Saturday morning was a neo-Nazi who posted online about killing Jews—and raged at Donald Trump for being insufficiently anti-Semitic.

Robert Bowers, 46, of Pittsburgh had an account on Gab, a social media site beloved by the far right. On Saturday morning, shortly before the shooting, Bowers posted an anti-Semitic conspiracy theory and what appeared to be a threat of violence.

“Screw your optics,” he wrote. “I’m going in.”

Shortly thereafter, around 10 a.m., he allegedly entered Pittsburgh’s Tree of Life synagogue during a crowded service and started shooting. Witnesses said he shouted, “all Jews must die” upon entering, according to multiple reports.

The only Robert Bowers in the Pittsburgh area with the same birth month and year as the synagogue suspect has an email address listed in public documents that is linked to the Gab account.

Bowers’ Gab handle was “OneDingo,” a screen name he used in connection with his legal name on computer programming sites for years. His Gab profile was verified. (Unlike Twitter, which verifies accounts that can prove their identities, Gab verifies accounts that pay for the status.)

A law enforcement source confirmed to The Daily Beast that “OneDingo” was Bowers' account.

The source also said that Bowers received a permit to carry firearms in July of 2016, and owned four of them. He obtained a hunting license less than a year later.

Shortly after the shooting, Gab deleted his profile and issued a statement claiming it has “zero tolerance” for terrorism and violence and boasting that it had contacted law enforcement after being alerted to the account.

But Bowers used his paid platform to promote neo-Nazi conspiracy theories and violence. He repeatedly posted about the Hebrew Immigrant Aid Society, a Jewish nonprofit that aids refugees, and on Saturday claimed the group was bringing “invaders in that kill our people.”

The claim echoes a neo-Nazi conspiracy theory underlying much of modern anti-Semitism, which falsely claims Jewish people are trying to “replace” whites through immigration. It’s why neo-Nazis at a torchlit rally in Charlottesville, Virginia, last year chanted, “Jews will not replace us.” The conspiracy theory is the cornerstone of some neo-Nazis’ white-supremacist ideology.

“There are no words to express how devastated we are by the events in Pittsburgh this morning,” the Hebrew Immigrant Aid Society wrote in a statement. “This loss is our loss, and our thoughts are with Tree of Life Congregation, our local partner Jewish Family and Community Services (JFCS) of Pittsburgh, the city of Pittsburgh and all those affected by this senseless act of violence. As we try to process this horrifying tragedy, we pray that the American Jewish community and the country can find healing.”

Bowers also posted conspiracy theories about George Soros, a Democratic donor whom another right-wing attacker allegedly targeted with a bomb this week, and who has become the subject of an anti-Semitic smear campaign by right-wingers. Other posts praised Hitler and targeted individual anti-fascist activists whom Gab users have routinely harassed. He shared a post complaining about charges against the far-right group the Proud Boys, some of whom were arrested for their involvement in a NYC brawl this month.

His header image was a neo-Nazi meme.

Bowers was also among a set of neo-Nazis who criticized President Donald Trump for being, as they saw it, not biased enough toward Jews. “Trump is a globalist, not a nationalist,” Bowers wrote on Gab. “There is no #MAGA as long as there is a kike infestation.”

Bowers also bashed Trump for being insufficiently supportive of the white supremacists of the deadly Charlottesville "Unite the Right" rally and of the Proud Boys, a violent alt-right gang.

Like Cesar Sayoc, the Florida Trump fan arrested Friday for allegedly mailing a dozen pipe bombs to Trump critics, Bowers used his account to threaten violence. He called for the killing of Jews and posted pictures of his guns, three Glock pistols.

He also appeared to have referenced Sayoc’s alleged bombing campaign. On Thursday, when far-right forums were in a frenzy over the bombs, he complained about “an amazing among of division on gab today. glad the overwhelming jew problem has been solved so we can now fight with each other.”

—with additional reporting by Adam Rawnsley and Michael Daly