People pray at a makeshift memorial near the Tree of Life synagogue in Pittsburgh, Pennsylvania, Oct. 31, 2018. Photo: Reuters / Cathal McNaughton.

A jury on Friday found Robert Bowers guilty of dozens of federal hate crimes for the killing of 11 worshippers at Pittsburgh‘s Tree of Life synagogue in 2018, the deadliest antisemitic attack in U.S. history.

Bowers, 50, now faces the penalty phase of his trial at the U.S. District Court in Pittsburgh in which the 12 jurors must weigh whether he deserves the death sentence.

Federal prosecutors charged Bowers with 63 counts, including 11 counts of obstruction of free exercise of religious beliefs resulting in death. The jury found him guilty on all counts, a spokesperson for the U.S. Attorney’s office in Pittsburgh confirmed.

During his trial, which began on May 30, jurors heard testimony from some of the survivors of the attack and evidence of Bowers’ antisemitism, including multiple posts attacking Jews made on a far-right website in the months leading up to the attack.

In the sentencing phase, prosecutors will try to show that aggravating factors were involved, making a case that Bowers carefully planned the attack and that he targeted vulnerable victims. Most of the victims were elderly.

Defense lawyers for Bowers have argued that a death sentence would violate the Constitution on the grounds that he suffers from major mental illness, including schizophrenia.

All 12 jurors must vote unanimously in order to sentence Bowers to death. Otherwise, he will face life in prison.