A defence psychiatrist has testified that Allan Schoenborn was psychotic when he killed his three children in 2008.A defence psychiatrist has testified that Allan Schoenborn was psychotic when he killed his three children in 2008. (CBC)

A psychiatrist says Allan Schoenborn was psychotic when he killed his three children in Merritt, B.C., in 2008.

Dr. Roy O'Shaughnessy told a first-degree murder trial in Kamloops that Schoenborn believed his children were being sexually abused and the only solution was to kill them and put them in heaven.

O'Shaughnessy — testifying Friday for the defence — said there was evidence going back a decade that Schoenborn had a chronic mental disorder but he often played down his illness and used alcohol to mask it.

A statement was also submitted to the court showing a social worker warned the children's mother, Darcie Clarke, to take action to protect her children after Schoenborn went to his children's school and threatened a girl he accused of bullying his daughter.

Crown psychiatrist to testify

The bodies of 10-year-old Kaitlynne Schoenborn and her younger brothers, Max and Cordon, were found by Clarke in their Merritt home.

B.C. Supreme Court Justice Robert Powers is hearing the trial without a jury. If Powers finds that Schoenborn was not of sound mind at the time of the killings, he could be found not guilty and sent to a psychiatric institution instead of prison.

The Crown prosecutor has contended that Schoenborn killed his children as an act of revenge against their mother.

A psychiatrist for the Crown is expected to testify next week.