Authorities are investigating anti-Semitic social media posts possibly made by the suspect in Saturday morning’s attack at a Jewish synagogue that killed 11 people, a law enforcement source tells PEOPLE.
Authorities confirmed at a Saturday news conference that the suspect is Robert Bowers, a Pittsburgh-area resident whose age authorities have not released and who was not previously known to police.
The suspect was taken to the hospital with gunshot wounds after surrendering to police, authorities said, adding that there is no continued threat to the public.
On Sunday morning, federal prosecutors said that Bowers had been charged the night before with 29 federal crimes, most of which carry a maximum penalty of death.
According to U.S. Attorney Scott Brady, Bowers faces 11 counts of murdering victims exercising their religious beliefs and 11 counts of using a firearm to commit murder as well as seven additional charges in connection with his alleged attack on the responding police officers at the scene, four of whom were wounded.
Brady said that during the rampage, which began about 9:50 a.m., Bowers allegedly talked about genocide and wanting to kill Jewish people. He was armed with three handguns and an AR-15 assault rifle, according to Brady.
Bowers will make his initial court appearance Monday afternoon, Brady said.
Police sources previously told local TV station that KDKA the the gunman yelled “all Jews must die” after entering the Tree of Life synagogue in the Squirrel Hill section of the city during the Saturday morning Shabbat service.
President Donald Trump condemned the attack as anti-Semitic violence and authorities announced it is being investigated as a hate crime.
According to the law enforcement source, investigators are looking at an account on the social media site Gab in which a user who is possibly the shooter writes, “Jews are the children of Satan.” In another post, the user reacts to the Hebrew Immigrant Aid Society (HIAS), a Jewish organization that works with refugees.
“He accused [the organization] of bringing in hostile invaders to live in the U.S.,” the source tells PEOPLE.
“Something touched him off this morning,” the source says, citing a post on the Gab account that read, “I can’t sit by and watch my people get slaughtered. Screw your optics. I’m going in.”
Pittsburgh Public Safety Director Wendell Hissrich told reporters on Saturday that authorities received a call about an active shooter at 9:54 a.m.
Robert Jones, the FBI Special Agent in Charge in Pittsburgh, said the suspect spent about 20 minutes inside the synagogue and was leaving when an officer engaged him. That officer was subsequently wounded, after which the suspect went back inside the synagogue to hide from SWAT officers, Jones said.
On Sunday, Jones said that Bowers is still in the hospital under guard, following surgery, and that while the investigation is in its early stages there is no indication that he acted with accomplices.
Jones on Saturday described the site of the shooting as “the most horrific crime scene I have seen in 22 years at the Federal Bureau of Investigation.”
“Members of the Tree of Life Synagogue — a place of worship — were brutally murdered by a gunman simply because of their faith,” he said.
Six people were also injured in the shooting, including four SWAT officers who responded to the scene.
Police Chief Scott Schubert said Sunday that one of the four wounded officers was released from the hospital on Saturday and that another could leave Sunday.
No children were killed in the shooting, according to authorities.
“We are going to get through this,” Schubert said Sunday. “We are going to continue on and show what Pittsburgh is made of.”
In response to the shooting, HIAS issued a statement saying, “There are no words to express how devastated we are by the events in Pittsburgh this morning. 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.”