A military defense contractor arrested after his teen son threatened violence at his California high school had an arsenal of weapons in his home, including a flame thrower and 29 assault rifles, nine of them unserialized, prosecutors said. Neal Anders, a deputy engineer at Innovative Defense Technologies, was arrested earlier this week, after his 14-year-old son said he was going to shoot up Rancho Bernardo High School, 10 News reported. The teen allegedly warned a small group of classmates “not go to school on Tuesday, the 30th, because he was bringing guns to school,” Deputy District Attorn…