An estimated 100 law enforcement officers are investigating at least seven crime scenes, sheriff's officials said. The shooter himself has been killed by police and several victims are now being treated at a local hospital.
"The shooter took his vehicle and rammed their fence and gate and entered the grounds on foot with a semi-automatic rifle", he added.
A shooter opened fire around 8 AM local time at a home in Rancho Tehama, north of Sacramento, before wounding at least three students at the Rancho Tehama Elementary School.
Jeanine Quist, an administrative assistant at Corning Union Elementary School District-one of the locations of the shooting-said that no one was killed at the school, but several people were injured.
In addition to the four people killed in the shooting, several people were injured, including children.
But police said Tuesday's incident spanned multiple shooting scenes involving multiple victims, and that three deaths, including the shooter, stemmed from the shootings.
"The insane thing is that the neighbour has been shooting a lot of bullets lately, hundreds of rounds, large magazines", Flint said. "We made it aware that this guy is insane and he's been threatening us".
The alleged shooter often fired multiple rounds during the early morning hours, and Flint said living near him was "hell". When asked how he was feeling, he replied: "I just feel like maybe there should've been more effort put into potentially stopping things like this". They heard the shooting from about a quarter-mile away and immediately corralled all of the students inside and locked down the facility.