A GUNMAN armed with a semiautomatic rifle walked into a suburban San Diego County synagogue in the United States and opened fire on the congregation Saturday, killing one person and injuring three in an attack that authorities believe was motivated by hate.

A 19-year-old was arrested in connection with the shooting, authorities said. The gunman entered Chabad of Poway on Chabad Way at about 11:20 a.m. and started firing.

He was identified as John T. Earnest, a Rancho Penasquitos resident. He is being questioned by homicide detectives.

Earnest appears to have written a letter posted on the Internet filled with anti-Semitic screeds. In the letter, he also talked about planning the attack.

“How long did it take you to plan the attack? Four weeks. Four weeks ago, I decided I was doing this. Four weeks later, I did it.”

Earnest, who is white, wrote that he was willing to sacrifice his future “for the sake of my people.” In the manifesto, he also took credit for an arson fire that blackened the walls of the Islamic Center in Escondido on March 24.

There were seven people inside the building at the time the fire erupted about at 3:15 a.m. but no one was injured.

(SD-Agencies)