A gunman named Robert D. Bowers, 46 years old, opened fire with a semiautomatic assault-style rifle, targeting members of a synagogue in Pittsburgh “and shot worshipers during Shabbat services, killing 11 and wounding six in the deadliest attacks on Jews in the history of the Unites States,” according to The Washington Post.

Robert D. Bowers is a Pittsburgh resident and wasn’t known to law enforcement. The shooting led him to be charged with 29 counts of federal crimes of violence and firearms offenses.

Bowers posted on social media anti-Semitic statements saying,”I can’t sit by and watched my people get slaughtered. Screw your optics, I’m going in.” hours right before the shooting, expressing his anger that a nonprofit Jewish organization has helped refugees settle in the United States.

On Saturday at 9:45 a.m. Bowers came in with an AR-15-style assault rifle and three handguns. Witnesses said that he was shouting “anti-Semitic statements and began firing.”

The police said that Bowers left the building and shot an officer before going back to the synagogue to hide. Officers responded to Bowers actions and exchanged gunfire. “Bowers suffered multiple gunshot wounds, was arrested and was taken to a hospital, authorities said.”

During the shooting, four police officers were wounded. Federal prosecutors charged Bowers with “obstructing exercise of religious beliefs resulting in death, using a firearm to commit murder during a crime of violence, obstructing exercise of religious beliefs resulting in an injury to a public safety officer and using a firearm during a crime of violence.”

According to USA Today, Bowers pled not guilty on Thursday “in a brief arraignment in federal court where prosecutors emphasized he faces the possibility of the death penalty.”