Police are still hunting for a motive in Monday's deadly shooting of a teacher at a Nevada middle school by a 12-year-old who brought a gun from home. The unidentified student also wounded two other boys with a semiautomatic handgun before he fatally shot himself. On Tuesday, student Jose Cazares told the "Today" show that slain math teacher Michael Landsberry, 45, had saved him, when he stepped between him and the gunman to protect him and other students. "I'm forever grateful for everything that he did," Cazaras' emotional mother said. Landsberry, a former Marine and member of the Nevada Air National Guard who had served two tours in Afghanistan, had worked in the school district since August 2001, according to his Facebook page. His brother said he leaves behind his wife Sharon and her two children. Authorities are still searching for a motive in the attack, but a student told the Reno Gazette-Journal that the gunman said he had been teased.