Mr Johnston said the neighbour, a woman, had a restraining order against the gunman.
"You could hear the yelling". The shooting, "it would be during the day, during the night, I mean, it didn't matter".
In her last few talks with her son, Neal's mother said he sounded desperate and despairing over his relationship with his neighbors, who he said were cooking meth and creating fumes that were harming his nine dogs.
"The sheriff wouldn't do anything about it", said Juan Caravez.
Tehama County Assistant Sheriff Phil Johnston told local news affiliate KCRA in an interview that "a number" of students had been airlifted from the scene, but that the school had been cleared and the students were now safe.
Johnston did not comment on the shooter's access to firearms.
Local media reports the as yet unnamed shooter is "well known" to local police, who have been called to his address at least six times in the past year over reports of gunshots and open fires. The district attorney, Gregg Cohen, told the Sacramento Bee the man in that case is Kevin Neal. She said she posted his $160,000 bail and spent $10,000 on a lawyer after he was arrested in January for stabbing a neighbor.
"Mom it's all over now", she said he told her.
"There was a neighborhood dispute ongoing", he added, but beyond that, "we don't know what the motives are for this individual to go on a shooting spree".
Students also were shot and wounded at a regional primary school, although police say no children are among the dead from what appeared to be "random", drive-by attacks.
All other students had been evacuated from the school, authorities said. He says he and his roommate told police that their neighbour was acting "crazy" and threatening them.
School officials' swift decision to lock the doors after hearing gunfire was "monumental" in saving the lives of countless children, Johnston said.