A grand jury handed up a revised indictment against John T. Earnest, 19, that adds four counts of discharging a firearm during crimes of violence.
He earlier pleaded not guilty to 109 federal charges, including committing a hate crime, and to state charges, including murder, in connection with the April 27 attack on the Chabad of Poway synagogue. Those charges also include attempted arson at a mosque in nearby Escondido a month earlier.
Prosecutors haven't decided whether to seek the death penalty.
Prosecutors say Earnest opened fire with a semi-automatic assault rifle and was carrying 50 extra rounds but had trouble reloading the weapon. During that pause, several members of the congregation, including an off-duty Border Patrol agent, chased him away, authorities said.
He drove away but was later captured.
The attack killed 60-year-old Lori Kaye, who was hit twice as she prayed in the synagogue foyer. Wounded were Rabbi Yisroel Goldstein, who was leading the service on the last day of the Jewish holiday of Passover, an 8-year-old girl and her uncle.
A federal affidavit filed earlier this month describes a deeply disturbed man filled with hatred toward Jews and Muslims, which is detailed in online writings. Earnest claimed to be inspired by the attacks on the mosques in New Zealand and the shooting at a Pittsburgh synagogue last fall, the affidavit said.
Court documents said Earnest dialed 911 after fleeing the house of worship in his car and said: "I just shot up a synagogue." He went on to tell the dispatcher that he did it "because Jewish people are destroying the white race," according to the affidavit. He was arrested without a struggle.
On Wednesday evening, the synagogue plans to dedicate a Torah scroll - a handwritten copy of biblical books that is considered the most sacred object in Judaism - in honor of Kaye.
"Lori was such a kind, loving soul, and she knew everyone here, so this is really an opportunity for the community to come together and heal, and celebrate the life of a very special person who was brutally taken from us," Goldstein said in a statement.
Copyright 2019 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.