Authorities say a series of shootings in rural Northern California left five people dead, including the shooter, and that two children were among the wounded.
Johnston says the shooter was "randomly picking targets".
Officials said they recovered a semi-automatic rifle and two handguns from the shooter.
All other student were transported to a safe location following the shooting. "This guy has been insane, and he's been threatening us and everything".More news: High lead levels found in fidget spinners
Tehama County Superintendent of Schools Rich DuVarney there were no student or staff fatalities. There are over 100 law enforcement officers at the school with up to five crime scenes.
Separately, three people were being treated at a hospital in Redding, about 80km north of the shootings.
He declined to release the name of the shooter but said the gunfire began with a domestic violence incident that neighbors reported. The FBI confirmed to CBS News they are sending agents from Sacramento, Redding, and Chico to assist with the investigation.
The roommates lived close to the gunman, and he said that the gunman was firing off rounds. "That evolved into multiple victims and multiple shots at the school", the deputy said.More news: Conor McGregor causes wild scene at Bellator 187
California Senator Jim Nielsen, who oversees the area of the shooting, said in a statement that his "heart goes out to the victims and loved ones affected by Tuesday morning's horrific shooting in Rancho Tehama", calling the incident "senseless violence".
Shots were fired at the school and some people were injured at the campus but no students or staff members died, Corning Union Elementary School District administrative assistant Jeanine Quist said by phone.
The Sheriff has enacted the officer involved shooting protocol, and multiple agencies are involved.More news: Hate Crimes Up In Minnesota In 2016
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