Authorities said the wife of a gunman who went on a rampage in Northern California was found dead, hidden under the floor inside their home.
Tehama County Assistant Sheriff Phil Johnston said Wednesday investigators discovered the body of Kevin Janson Neal's wife riddled with bullets under floor boards.
Neal "cut a hole in his floor, murdered — shot her probably late Monday, and literally just put her body in the floor and covered it up," Johnston said, adding that investigators believe her slaying was the start of the rampage.
The gunman shot and killed four other people and wounded 10 at different locations around the rural community of Rancho Tehama Reserve, including an elementary school, before he died in a shootout with police. Seven children were among the injured.
"This was a tragic event and a truly heinous crime," said Sean Ragan, the special agent in charge of the FBI's Sacramento Field Office.
At the time of the attack, Neal was out on bail for a charge of stabbing a neighbor. Neighbors had also complained about him firing off hundreds of rounds of ammunition and the assistant sheriff acknowledged officers visiting the home on several occasions.
"He was not law-enforcement friendly," Johnston said. "He would not come to the door."
Johnston said the gunman was facing charges of assaulting one of his neighbor in January and that she had a restraining order against him.
Tehama County District Attorney Gregg Cohen said he was out on $160,000 bail and did not have the opportunity to return to court where prosecutors could push for an increase in that amount.
"That's his right," Cohen said. "A person's innocent until proven guilty so even though there might be a rush to justice in this situation as far as he should have been tried and convicted, that's not how our system works."
It's not clear what the terms of Neal's bail were, but his many contacts with authorities raised questions of why he was out of custody and able to use a semi-automatic rifle and two handguns to go on a 25-minute shooting spree that began with the killing of two neighbors in an apparent act of revenge before he went looking for random victims.
The gunman's sister, Sheridan Orr, said her brother had struggled with mental illness throughout his life and at times had a violent temper.
"He was an all American kid with a good family. Mental illness took over," Orr told NBC News.
Orr, who said she had not talked to her brother in months, said she believed he was addicted to drugs.
"We’re stunned and we’re appalled that this is a person who has no business with firearms whatsoever," Orr said. "Our deep, deep sympathy for the victims and it sounds trite but our hearts are breaking for them."
Orr added, "If we can do any good to make people realize there must be some gates on people like this from getting guns," she paused. "This is the same story we’re hearing more and more."
Cristal Caravez and her father live across a ravine from the roadway where the gunman and his first victims lived.
She said they and others heard constant gunfire from the area of the gunman's house, but couldn't say for sure it was him firing.
"You could hear the yelling. He'd go off the hinges," she said. The shooting, "it would be during the day, during the night, I mean, it didn't matter."
She and her father, who is president of the homeowners association, said neighbors would complain to the sheriff's department, which referred the complaints back to the homeowners association.
"The sheriff wouldn't do anything about it," said Juan Caravez.
Neal's mother told The Associated Press her son, who was a marijuana grower, was in a long-running dispute with neighbors he believed were cooking methamphetamine.
The mother, who spoke on condition she be named only as Anne, lives in Raleigh, North Carolina, where she raised 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. Neal's mother said the neighbor was slightly cut after Neal grabbed a steak knife out of the hand of the neighbor who was threatening him with it.
She wept as she told The Associated Press she spoke to Neal on the phone on Monday.
"Mom it's all over now," she said he told her. "I have done everything I could do and I am fighting against everyone who lives in this area."
She said Neal apologized to her during their brief conversation, she thought for all the money she had spent on him, saying he was "on a cliff" and the people around him were trying to "execute" him.
"I think the motive of getting even with his neighbors and when it went that far — he just went on a rampage," Johnston said.
Police said surveillance video shows the shooter unsuccessfully trying to enter a nearby elementary school after quick-thinking staff members locked the outside doors and barricaded themselves inside when they heard gunshots.
Johnston said the gunman spent about six minutes shooting into Rancho Tehama Elementary School before getting "frustrated" and driving off to continue shooting elsewhere.
"It is monumental that the school went on lockdown," Johnston said. "I really, truly believe that we would have had a horrific bloodbath in that school if that school hadn't taken the action when they did."
Johnston said the rampage by a "mad man on the loose" ended when a patrol car rammed the stolen vehicle the shooter was driving and killed him in a shootout.
Johnston said officials received multiple 911 calls about gunfire at an intersection of two dirt roads. Minutes later, more calls reporting shots flooded in from different locations, including the school.
Witnesses reported hearing gunshots and children screaming at the school, which has one class of students from kindergarten through fifth grade.
For his part, Johnston promised: "We will move forward and we will start the healing process."
NBC Bay Area's Brendan Weber contributed to this report.