MARTINEZ — A Concord man who was arrested after making anti-Semitic threats of a mass shooting on an online video game forum was convicted for four felonies and a misdemeanor this week, prosecutors said. Ross Farca, 25, was convicted of possessing an assault rifle he allegedly made himself, as well as making criminal threats online and threatening the Concord officer who investigated his case during a search of his home. Farca was also convicted of a hate crime, prosecutors said. Farca was arrested two years ago after he allegedly used a screenname with a reference to Adolf Hitler and the...