A Twentynine Palms man was arrested Wednesday after he threatened to shoot up a school and threatened teachers. According to a Sheriff’s press release, deputies were notified about noon Wednesday that Matthew Ross, 18, a student at Black Rock High School, located in the 59200 block of Sunnyslope Drive in Yucca Valley, threatened to shoot, stab, and assault school staff. Deputies served a search warrant on Ross’s home in the 7700 block of Sahara Avenue in Twentynine Palms, and found a loaded rifle, hundreds of rounds of ammunition for a rifle and shotgun, large hunting knives, and crossbows. Matthew Ross was arrested for investigation of making criminal threats and booked at the West Valley Detention Center, with his bail set at $50,000.