The man accused of opening fire inside a synagogue in Pittsburgh is a local who regularly posted anti-Semitic messages on social media filled with slurs and conspiracy theories.
Two hours before the shooting he wrote online: “I’m going in”.
Here’s what we know about him.
His name is Robert Bowers and he’s 46 years old
He lives in Pennsylvania, according to authorities, and is a registered voter with “no affiliation” in Allegheny County.
He has reportedly bought six guns in the last 22 years
Mr 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.
But he does not have a criminal record and was not known to police, law enforcement officials said.
He regularly used a chat site for ‘free speech’
Mr Bowers was a regular user of the chat website Gab.com, which promotes itself as a “social network that champions free speech, individual liberty and the free flow of information online”.
It is a popular gathering space for the alt-right.
In a statement, Gab.com said that when it learned Mr Bowers had a profile on its site, it took “swift and proactive” action to contact law enforcement immediately.
It said it backed up Mr Bowers’ user data and suspended his account, then told the Federal Bureau of Investigation (FBI) what it had done.
“Gab unequivocally disavows and condemns all acts of terrorism and violence,” it said.
His online posts were angry
An archive of Bower’s Gab posts since he joined the site in January showed an angry, anti-Semitic 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.
He posted two hours before the shooting
Two hours before the shooting, Mr Bowers posted on 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,” he wrote.
The gunman reportedly shouted anti-Semitic phrases during the shooting, which left 11 people dead and six injured, including four police officers.
He has been a vocal critic of Donald Trump
Mr Bowers said on Gab.com that US President Donald Trump was a “globalist” who did nothing to stop the “infestation” of the United States by Jewish people.
“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, the slogan frequently used by Mr Trump.
He now faces the death penalty
The Department of Justice will be filing hate crime and other criminal charges against Mr Bowers, according to Attorney-General Jeff Sessions.
Those charges could lead to the death penalty.
“The actions of Robert Bowers represent the worst of humanity. We are dedicating the entire resources of my office to this federal hate crime investigation and prosecution,” Scott Brady, the US attorney for western Pennsylvania, said.