(REUTERS) - The FBI on Monday (April 29) said it received multiple tips about a security threat minutes before a gunman opened fire in a California synagogue, killing a woman and wounding three others, but did not have enough detail or time to prevent the attack.
Police are investigating what motivated a 19-year-old suspect to open fire on the Chabad of Poway synagogue in suburban San Diego on Saturday, including whether to bring hate crime charges against the man who surrendered to police shortly after the attack.
The FBI said it received tips about an online post referring to a potential attack that did not include "specific"information about the post's author or location.
Investigators immediately began working on identifying the author, but the shooting began only five minutes after the tips arrived.
"The FBI thanks the alert citizens who saw and reported the post," the bureau said in a statement.
Members of the synagogue later on Monday were due to bury Lori Gilbert Kaye, 60, who died in the attack six months to the day after 11 worshippers were killed at a Pittsburgh synagogue in the deadliest attack on American Jewry.
The alleged gunman, identified by police as John Earnest, fled the scene and eventually called police in order to surrender.
Earnest, who is being held without bail, appears to have authored an online manifesto in which he claimed responsibility for a pre-dawn arson fire at a nearby mosque last month and drew inspiration from the mass shooting at two mosques in New Zealand that killed 50 people in March.
His parents expressed shock and sadness in a statement on Monday, saying their son had become "part of the history of evil" perpetrated on Jewish people.
"How our son was attracted to such darkness is a terrifying mystery to us," the statement read. "Our heavy hearts will forever go out to the victims and survivors."
The parents added that they are cooperating with investigators.
When the gunfire began, Oscar Stewart, 51, a veteran of both the US Navy and Army who served a tour in Iraq, recognised the sound immediately.
He said in a Monday interview that for a moment he began running toward the exit with other congregants before he turned around and headed toward the gunfire.
"I was an instrument of God," he said. "I had no conscious effort in what I was doing."
He charged the gunman, screaming, "I'm going to kill you!"
The shooter, who had stopped firing, looked frightened and fled the synagogue, with Stewart in close pursuit, he said.
Another worshipper, an off-duty US Customs and Border Protection agent named Jonathan Morales who was armed, also ran outside and fired several shots at the gunman's car as he drove away.
Almog Peretz, an Israeli citizen visiting his family, was hit by shrapnel but still managed to help shepherd children to safety, witnesses said.
His nine-year-old niece, Noya Dahan, was also wounded by shrapnel. Her family moved to the United States from Israel in search of a safer life after their home was repeatedly shelled by Palestinian rockets.
Kaye, one of the synagogue's founding members, was a deeply caring member of the community, her friends said.
When one congregant developed breast cancer, Kaye drove her to every appointment and helped take care of her children, said Rabbi Yisroel Goldstein, who was shot in both hands during the attack and lost a finger.
"She is a person of unconditional love," Goldstein told reporters, adding that he felt Kaye "took the bullet for all of us".
In a Facebook post, a friend, Audrey Jacobs, called her a"woman of valor" whose final act was to protect others.