Yolanda Tijerina's tirade, which seemed directed at no one in particular, drew a crowd of neighbors and staffers at Meridian Children's Center.
"I think you killed my son!" shouted Tijerina, whose 4-year-old boy, Lars Sanchez, attended the school. "I think you killed my son. I have panic attacks."
Principal Elizabeth Blackwell's call led to an investigation by mental health and child welfare officials, according to county documents recently obtained by The Times. The boy's grandmother told officials that the mother had "episodes," and his adult sister told them she believed the boy was in danger.
The documents, released by the county Department of Children and Family Services under a 2008 disclosure law, show in chilling detail how even dramatic evidence of a mother's illness was not considered sufficient grounds for removing a child from her care.
The department closed the case in a matter of days, saying that allegations of emotional abuse against Lars could not be substantiated. The home was considered "stabilized."
On July 18, shortly after daybreak, Lars' grandmother found him dead in the bedroom he shared with his mother. Tijerina was on the floor next to the bed, her left wrist slashed to the bone. A knife lay next to her.
Supervisor Gloria Molina, publicly condemned the county's handling of the case as "a big mistake." As is routine, the social workers involved were assigned to desk duty pending a review.
The brutal death of Lars Sanchez underscored a significant weakness of the child welfare system: gauging the risks of a caregiver's mental illness.
Mental illness in itself does not disqualify one from raising a child.
Child welfare officials must consider whether the person is under effective treatment, whether the child's care is overseen by other stable adults, and whether the illness results in abuse or neglect of the child. These are determinations that can be a challenge even for psychiatric experts.
"Social workers are not necessarily trained to assess a parent's mental health," said Charles Sophy, medical director with the Department of Children and Family Services.
Nor are they necessarily privy to key information about the parent or other caregiver. For instance, they can't access mental health treatment records without the patient's permission. Without that, the decision may be largely based on a one-on-one interview.
"Mental illness is easy to hide sometimes," Sophy said. "You can put on a smiling face when I knock on your door, and I will never know that you tried to kill yourself last week."
Nevertheless, social workers confront and decide the issue frequently.
Almost a fifth of the 4,468 children removed from their homes by the family services agency last year were removed primarily because of a parent's mental illness.
Lars' death has already prompted some changes.
The department has sped up its plans for an internal hotline allowing social workers to consult with Sophy or his medical staff when mental illness is at issue, Sophy said.
But social workers in Lars' case were not acting entirely on their own, interviews suggest. According to two sources with knowledge of the case, the social workers called in evaluators from the county Department of Mental Health to do an assessment of the mother, and the findings persuaded them that she was not a threat.