For nearly two weeks, the young boy and his sister mostly huddled at home, alone and terrified of what lay behind the master bedroom door.
The facts known to them were these: Their parents had argued and their father--wielding a butcher knife--had emerged from the room with stern warnings. Say nothing and do not look behind the door, he told them.
On Sunday night, the boy finally went for help. Fearful of defying his father, he instead walked to a local supermarket and shoplifted, hoping the police would catch him, take him home and unravel the mystery.
It worked. On the bedroom floor inside the family's tidy white house, officers found the decomposing body of the children's mother, Janice Castorena, 38.
"She had a stab wound to the chest, and she had been dead for quite some time," said Michael Heenan, spokesman for the Sacramento Police Department. "The children never opened the bedroom door. I think for a long time they were in complete denial" about what lay behind it.
On Monday, police were searching for the children's father, schoolteacher Robert Castorena, who was last seen driving the family's blue Volvo sedan and believed to be heading for Los Angeles, where he has family and friends.
Investigators suspect that Janice Castorena was killed Oct. 1 and that her husband fled two days later.
The victim was a physical therapist who had worked since March for Theramerica, a firm that dispatches physical therapists to hospitals and nursing homes.
She had worked as recently as two weeks ago, but the agency had been unable to reach her since then. The reason became evident when another therapist in the Sacramento area heard news reports about the slaying and called the company's Emeryville office.
The children--a 14-year-old girl and her 8-year-old brother--were in protective custody Monday. Heenan said they were in shock and had received counseling from volunteer chaplains Sunday night.
"They were in complete breakdown mode," Heenan said. "I think the reality of the situation finally came crashing down."
Robert Castorena, 38, taught social studies at C.K. McClatchy High School in Sacramento until Sept. 16, when he abruptly and inexplicably quit. School district officials said he had also taught at several junior high schools in the area beginning in 1986.
The Castorenas' daughter was a freshman at the high school until late September, when her mother removed the girl from classes and said she would be schooled at home.
The family lived in an attractive, middle-class neighborhood about five miles south of the state Capitol. Their rented home sits on a corner, with two large elm trees in front and a broken hammock strung between citrus trees out back.
Neighbors said the Castorenas moved in about six or eight months ago and did not mingle with other residents on the block.
One neighbor, Robin Casey, said her 16-year-old son, Brian, and the Castorenas' daughter met and became friends at a nearby playground. For the last two weeks, the girl would call or drop by daily, never letting on that there was anything amiss. Rather, Casey said, the girl made up stories to disguise the hideous circumstances at home.
At one point, Casey became curious about the girl's parents and inquired about them. The girl said her parents had gone to Lake Tahoe to celebrate their wedding anniversary.
"This is the first time she has decided to leave us," Casey said the girl replied.
Last weekend, the girl said her parents were grocery shopping. Casey remembers the teenager saying that they didn't want to bring her or her brother because "they needed some time together."
"I couldn't believe that this little girl had a mom at home that was murdered in the bedroom," Casey said.
Police said the family had previously lived in Lodi and Fresno.
Heenan said police in Lodi had once been called to a domestic disturbance at the Castorena home but that Janice Castorena sent them away, denying any trouble had occurred.
Based on interviews with the children, police said the Castorenas had argued in their bedroom for two days, culminating Oct. 1. The next day, their father emerged and ordered them not to disturb their mother, open the door or say anything to anyone.
Periodically over the next two days, he allegedly threatened each of the children. His daughter said Castorena held a knife to her throat and said he would kill her if she breathed a word about the fight.
The boy said he decided to shoplift in order to summon help without directly contacting authorities, which would have been against his father's orders.
"In his mind, it was the only way to get someone to the house," Heenan said.
The boy was caught Sunday night by a Raley's Supermarket security guard. After questioning, he broke down and said he thought his mother might be dead.
When police arrived at the home, the stench of the decomposing body was overpowering. A large butcher knife was found near the body.
Heenan said the children were in good physical condition. Officers found a loaf of bread on the kitchen table and other food in the house.
Times staff writers Carl Ingram and Dan Morain contributed to this story.