<p>A middle school student in Sparks, Nev. opened fire on his classmates Monday morning, killing a math teacher, and then turned the semi-automatic handgun on himself. He also injured two 12-year-old boys, both of whom are in stable condition. The teacher, Michael Landsberry, was a veteran, and a witness told the Reno Gazette-Journal that the student shot Landsberry after he ordered him to put down the weapon.</p>