The man accused in a shooting at a Pittsburgh synagogue Saturday morning screamed anti-Semitic epithets, including "All Jews must die," as he fired at random, a law enforcement official told USA TODAY.
Bowers, 46, was armed with one assault rifle and three handguns during his shooting spree inside the Tree of Life synagogue as innocents were worshipping, the FBI said.
He walked into the synagogue shortly before 10 a.m. By the end of the 20-minute attack, 11 were dead and six left seriously injured, including several officers.
Just before entering the building, a social media account appearing to belong to Bowers posted an anti-semitic message to the website Gab, a fringe social media website utilized in large part by white nationalists and members of the far-right.
"I can't sit by an watch my people get slaughtered. Screw your optics. I'm going in," the post said.
He was charged late Saturday on 29 criminal counts, including 11 federal hate-crime charges. Among the charges were also 11 counts of using a firearm to kill. Those charges alone carry a maximum penalty of death, though no decision has been made about the death penalty.
PHOTOS: Pittsburgh synagogue shooting
The profile includes an array of anti-Semitic comments and conspiracy theories. The anti-Semitic rants on social media prompted authorities to designate the FBI as the lead agency to investigate the attack as a hate crime.
In the post just before the shooting, the organization HIAS, the Hebrew Immigrant Aid Society, was mentioned. The post accused the agency of bringing "invaders in that kill our people."
It's unclear who Bowers meant when saying "our people."
On the page appearing to belong to Bowers, he wrote about a number of conspiracy theories and his stark opposition to immigration, especially the migrant caravan that has drawn ire from the Trump administration.
Bowers, though, said he did not vote for Trump. He seemed to believe the president was too soft on those of the Jewish faith and wrote that Trump was surrounded by those individuals, preventing him from keeping true to his slogan: "Make America Great Again."
Gab, in a statement, said it was "saddened and disgusted" by the attack but defended its ability to protect free speech. The site backed up the shooter's profile then suspended the account.
But profiles like Bowers' are common on Gab. Anti-Semitic comments, conspiracy theories and wild pro-Trump posts are the norm as the website doesn't keep as tight of rules compared to mainstream sites like Facebook, Twitter and Instagram.
"Gab’s mission is very simple: to defend free expression and individual liberty online for all people. Social media often brings out the best and the worst of humanity," the statement said. "Criminals and criminal behavior exist on every social media platform."
Linda Lohr, who used to live across the street from Bowers, said she was stunned when she saw the news. She said Bowers, who she knew as "Rob," was living with his grandfather and she'd frequently see him outside mowing the grass.
"I would have never thought he was a hatemonger," she said. "You think you know what your neighbor is like, then you find out something like this."
Lohr said it seemed to her that Bowers did not have a job. She said Bowers moved out of the home when his grandfather passed away some time ago, approximately five to seven years ago.
"I would say hello as I was in my garden and we would talk about the flowers and all the weeds," Lohr said. "I'm stunned that it was someone who lived just across the street. I can't comprehend it."
Another neighbor, Philip Dodge, said he lived next door to Bowers and his grandfather.
"I honestly didn't know them that well," Dodge said. "Mr. Jenkins passed away a while ago."
After his rampage, Bowers was confronted by a lone Pittsburgh officer as he attempted to leave the synagogue about 10 a.m., the FBI said. The confrontation and subsequent shootout forced Bowers to barricade himself inside the synagogue.
He was taken into custody after being shot multiple times and is in fair condition at the hospital.
Law enforcement officials at a news conference Saturday afternoon said Bowers was not known to authorities, making it hard to foresee the tragedy.
Bob Jones, Pittsburgh bureau's FBI Special Agent in Charge, said it was the "most horrific" crime scene he'd seen in 22 years. He said the victims were "brutally murdered" and was done "simply because of their faith."
Federal charges against Bowers are expected to be filed soon, possibly as early as Saturday evening. Attorney General Jeff Sessions said the charges could lead to the death penalty.
Victims have not been named, but Pennsylvania Attorney General Josh Shapiro said the shooting occurred at the synagogue during a baby-naming ceremony.