Federal authorities hit a white supremacist accused of murdering 11 Jews at a Pittsburgh synagogue with more than a dozen new charges on Tuesday.

Robert Bowers, 46, allegedly opened fire on the Tree of Life Synagogue in Pittsburgh in October and made made anti-Semitic comments on the extremist-friendly social network Gab shortly before the attack. He was charged in federal court that month with dozens of offenses including 11 murder charges. Feds added 19 new charges on Tuesday, including 11 counts of hate crimes resulting in death and two counts of hate crimes involving attempted murder, as well as several others. All told, Bowers faces 63 criminal counts.

Bowers called Jewish people “the children of Satan” in his Gab profile. In the days before the shooting, Bowers authored increasingly anti-Semitic posts. On October 10, he posted about the Hebrew Immigrant Aid Society (HIAS), a Jewish charity that was hosting charity events for immigrants. One of the events was at the Dor Hadash congregation. Dor Hadash and another Jewish congregation share the same Pittsburgh synagogue as Tree of Life, according to Tuesday’s superseding indictment filed in federal court.

Bowers accused HIAS and its associated congregations of bringing “hostile invaders to dwell among us.” The claim is part of a white supremacist conspiracy theory that falsely claims Jewish people are trying to promote immigration to make countries less white. Elsewhere on Gab, Bowers posted anti-Semitic and neo-Nazi memes.

According to the indictment, Bowers drove to the synagogue the morning of October 27, when all three congregations were worshipping. Before entering, Bowers posted a final message to Gab, once again referencing the conspiracy theory. “HIAS likes to bring invaders in that kill our people,” he wrote. “I can't sit by and watch my people get slaughtered. Screw your optics, I'm going in.”

Once inside, he carried out a massacre with four guns: three handguns and one rifle, according to the indictment. While carrying out the massacre, Bowers “made statements conveying his anti-Semitic beliefs and indicating his desire to ‘kill Jews,’” according to the indictment. He reportedly told his arresting officers that the Jewish people he allegedly massacred were “committing genocide to my people.”

Those alleged statements are part of the basis for the 13 new hate crime charges, which including 11 counts of hate crimes resulting in death, and two counts of hate crimes involving attempted murder. Federal authorities also charged him with six new counts relating to firing a weapon during the attack.

Bowers previously pleaded not guilty to the charges against him in October. If convicted, he faces the death penalty.