John T. Earnest appears for his arraignment hearing last month in San Diego. Earnest was charged Thursday with federal hate crimes and civil rights violations. (Nelvin C. Cepeda/AP)

The 19-year-old accused of opening fire in a synagogue near San Diego last month, killing one and wounding three others, was charged Thursday with 109 federal hate crimes and civil rights violations — making it possible for him to face the death penalty, authorities said.

John T. Earnest had been facing state charges of murder and attempted murder in connection with the April 27 attack on the Chabad of Poway, Calif. Federal authorities added dozens of charges of their own, alleging in a criminal complaint that the shooting was motivated by Earnest’s animus toward Jews and that he was also responsible for a March 24 arson at a mosque in Escondido, Calif.

“This federal complaint alleges that these crimes were explicitly motivated by hatred toward the Jewish and Muslim communities,” U.S. Attorney Robert Brewer said at a news conference to announce the charges.

The federal counts included obstruction of free exercise of religious beliefs resulting in death, hate-crime acts and damaging religious property. Brewer said prosecutors in the Southern District of California brought 54 charges each of obstruction and hate-crime acts to represent “one count for every person in the synagogue on April 27.” Among those present, he said, were 12 children.

“Our actions today are inspired by our desire to achieve justice for all of the victims and their families,” Brewer said. He said the federal and state cases will proceed at the same time, and Earnest is expected to appear in federal court next week.

Although the charges against Earnest carry a possible death sentence, federal prosecutors still must decide whether they will seek that penalty.

The attack on the Chabad of Poway came on the last day of Passover, a major Jewish holiday, and six months after the massacre at Tree of Life synagogue in Pittsburgh, where a gunman killed 11 and wounded six others.

Brewer said Thursday that Earnest had posted an online manifesto citing the Pittsburgh attack, as well as the recent attacks on mosques in New Zealand.

Brewer said that Earnest wrote in the post, “As an individual, I can only kill so many Jews.”

Lori Kaye, 60, of Poway was killed, and the three others wounded included a child. The San Diego County sheriff has said the shooter’s rifle malfunctioned after he fired inside the synagogue, and that might have prevented more carnage. The complaint says Earnest unsuccessfully tried to reload, and members of the synagogue moved to confront him. Brewer said Earnest had 60 rounds of ammunition.

The gunman fled but called 911 from his car and offered a chilling account of his motivation, Brewer said.

“I just shot up a synagogue,” Earnest said, according to Brewer. “I’m just trying to defend my nation against the Jewish people. They’re destroying our people.”