In the early morning of Oct. 3, in a quiet, upscale San Luis Obispo neighborhood, John "Mike" Rivard, 48, shot and killed his wife Barbara, 44, and their daughter Olivia, 7.
Then he used the same gun to take his own life.
The Rivards' two other children, Jack, 4, and Madeleine, 5, survived unharmed.
Barbara Rivard's parents are raising the two children in Southern California.
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No one will ever know why the murder-suicide took place or exactly what happened in the final moments before the Rivards died. Mike Rivard had no drugs or alcohol in his blood-stream when he shot and killed his wife and daughter. Barbara Codding Rivard's toxicology report showed traces of cough syrup and antidepressants.
The incident sparked an outpouring of grief from people who knew the Rivard family and many who did not.
"When this whole thing came loose, it unhinged a lot of people in the congregation," said the Rev. Jim Blades, pastor of the First Presbyterian Church of San Luis Obispo.
Mike Rivard and his children attended that church routinely.
"A while after the tragedy, after people were able to recover from their numbness, we used it as an opportunity to talk about the larger subject of loss and children," Blades said.
He was left with the difficult job of counseling the congregation through its grief.
Olivia Rivard and her two siblings attended Sunday school at the church.
Other students in the class, accustomed to their presence also mourned.
For the children who knew the family, it is the simple things they will remember such as Mike Rivard picking them up from Sunday school, playing with them at the gym or meeting for ice cream.
"When someone elderly dies it seems a normal part of existence," Blades said. "But when a child dies, it is like a period before the end of a sentence."
The county's Child Welfare Services received seven calls about the Rivard family before November 2006. After the deaths, officials asked themselves if there was more they could have done to prevent the deaths.
One high-ranking administrator doesn't believe there was.
"There was never a time where any neglect or abuse referrals rose to a level that we would have even considered taking (the children) away," said Tracy Buckingham, assistant director of social services.
Hours after learning about the murder, Buckingham said she reviewed the Rivard family's file and pulled together every social worker who had contacted the family.
"I told them that there was absolutely nothing more they could have done," she said. "We had every reason to believe the family was connected to the resources it needed."
Whenever a child dies in a suspicious manner, Child Welfare Services must report its history with the child or family to the state.
According to Buckingham's report to state officials, Mike Rivard, a San Luis Obispo psychiatrist, made all but one of the child-welfare referrals in regard to his wife's addiction to prescription drugs. He made the calls around the two times he filed for divorce.
Court records show the couple had a history of marital problems. Mike Rivard filed for divorce in December 2003 but withdrew the divorce papers in March 2004, only to file again in August 2004. Barbara Rivard was treated repeatedly for a prescription drug addiction, the court records showed. She was a stay-at-home mother.
After interviewing the family, social workers substantiated two of the referrals and made sure the family was connected with services, such as therapy and drug counseling, Buckingham said. Then the referrals were closed. Formal cases were never opened.
Social workers said they respond to every report they receive about suspected child abuse. They interview the children and family members involved, along with professionals, such as teachers or doctors, to see if abuse or neglect has occurred. They will open a case if they believe the family requires further monitoring.
The last referral on the Rivards was made in November 2006 by an anonymous source regarding broad concerns about Mike Rivard's behavior. The caller gave few details.
Social workers and police responded to the call, interviewed the parents, children and the family pediatrician. They found no evidence that the children were at risk, Buckingham said.
Police officers never felt the Rivard children's immediate psychological or physical welfare was at risk, police officials said.