The 19-year-old San Diego man named John Earnest has also claimed responsibility for the mosque arson in the nearby town of Escondido. He wrote in his manifesto: “I scorched a mosque in Escondido with gasoline a week after Brenton Tarrant’s sacrifice. Tarrant was a catalyst for me personally.”
He added: “He showed me that it could be done.”
In the manifesto the author, who identified himself as John Earnest, said he was inspired by the attack on two Christchurch mosques last month, and the Pittsburgh shooting’s last year.
The San Diego attack comes exactly six months after a shooting in Pittsburgh were Robert Bowers killed 11 people at the Tree of Life synagogue, thought to be the worst anti-Semitic attack in recent US history.
The racist, anti-Semitic manifesto that police are investigating in relation to the San Diego shooting makes 10 references to Robert Bowers, who the author John Earnest calls an “inspiration”.
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The gunman opened fire at the synagogue in California on Saturday, killing one woman and wounding three other people, police said.
Mr Earnest was arrested after the attack, in Poway, north of the city of San Diego.
The synagogue had been hosting a Passover celebration when the gunman burst in.
Police did not suggest a motive but US President Donald Trump said the attack appeared to be “a hate crime”.
San Diego County Sheriff Bill Gore told reporters that investigators were reviewing the suspect’s social media activity and examining a virulently anti-Semitic “open letter” published online.
Sheriff Gore said: “During the shooting, four individuals were wounded and transported to Palomar hospital.
“One succumbed to their wounds.
“The other three are in stable condition.”
Mayor Steve Vaus said the synagogue’s rabbi had been shot in the hand.