(Sparks, NV) -- Police are looking for a motive after a 12-year-old Nevada boy opened fire at a middle school Monday, killing a teacher and wounding two students before turning the gun on himself. Officials say out of respect for the family of the shooter, his identity is not being released at this time. It's believed the boy used a Ruger nine-millimeter pistol he brought from home. Sparks Middle School teacher Mike Landsberry was killed. The two students who survived the shooting are stable and recovering.