SPARKS, Nev. (AP) — A student at a Nevada middle school opened fire on campus just before the starting bell Monday, wounding two boys and killing a teacher who was trying to protect other children, Sparks police and the victim's family members said. Twenty to thirty students witnessed the tragedy at Sparks Middle School that also left the lone suspected gunman dead, police said. It's unclear whether the student committed suicide, but authorities say no shots were fired by law enforcement.