B.C.'s child protection watchdog will investigate the killing of three Merritt children by their father to determine if government action or policy contributed to their deaths.

John Greschner, the chief investigator with B.C.'s Representative for Children and Youth, said Tuesday his investigation into the deaths of Kaitlynne Schoenborn, 10, and her brothers Max, 8, and Cordon, 5, will take months.

At the end of it, Greschner said his office will issue a public report, possibly with recommendations.

"This will be an investigation into the death of these particular children," he said.

Greschner said his office investigates cases when it's possible the policies or practices of a public body may have contributed to the deaths of children.

"We have not concluded that is the case. We have concluded there are things (in this case) that need to be looked at," he said.

Allan Schoenborn was found guilty in February of the first-degree murder of his three children. B.C. Supreme Court Justice Robert Powers, however, ruled the man was not criminally responsible because a mental disorder robbed him of his ability to know his actions were wrong.

Psychiatrists testified at the man's trial he was delusional when he stabbed his daughter to death and smothered the two boys on April 6, 2008. The children were found by their mother Darcie Clarke.

The Crown argued at the trial Schoenborn killed the children to exact revenge on Clarke, who had earlier told him she wanted to end their 14-year common-law relationship.

Social workers had been involved with the Schoenborn family extensively in the months before the murders amid reports of domestic conflict between Schoenborn and Clarke. There had never been a report of violence against the children.

Greschner would not say whether Schoenborn will be interviewed as part of the investigation. The man is being housed in secure psychiatric facilities under the supervision of B.C.'s Review Board at the Forensic Psychiatric Institute in Port Coquitlam

The evidence from Schoenborn's criminal trial will be a valuable source of information to the investigation, but Greschner noted his office also has the ability to issue subpoenas and compel evidence from anyone it deems important to the case.

Evidence is taken under oath, he said. Greschner suggested a wide range of individuals - from social workers to police officers and teachers - could be questioned.

"We explore all of the issue that arise . . . and we issue a public report," he said.

Recommendations, if any are made, can relate to any public agency, Greschner said. The report will also be presented to the government's select standing committee on children and youth.

The B.C. Representative for Children and Youth is an independent agency created by government in 2008, following an independent review in 2005 of the province's child protection system.