The US student who killed a teacher and injured two classmates in a school shooting before taking his own life was 12 years old.
Authorities in Nevada say they are withholding the name of the Sparks Middle School student out of respect for his family.
But School District Police Chief Mike Mieras released the seventh-grader's age at a news conference today.
District police say the boy brought the weapon used in yesterday's shooting from home.
Police say his parents are co-operating with them and could face charges in the case.
Also at the new conference, police lauded the actions of 45-year-old maths teacher and former Marine Michael Landsberry. They say he tried to stop the rampage before he was fatally shot in the chest.