A mother who admitted killing eight children in a home in Cairns will not face a criminal trial, after Queensland’s Mental Health Court ruled she was of “unsound mind” when they were fatally stabbed.

The bodies of the four boys and four girls, aged between two and 14, were found in the house on Murray Street at Manoora on December 19, 2014.

Raina Mersane Ina Thaiday, also known as Mersane Warria, who was the mother of seven of the victims and aunt of the other, was charged with their murders.

But the court ruled Thaiday, now 40, was not responsible for her actions because she suffered a psychotic episode, triggered by undiagnosed schizophrenia.

The ruling — made last month but only allowed to be published today — meant all charges against her would be dropped and the case discontinued.

Under Queensland law, a person who is found to be of unsound mind is declared not to be criminally responsible for their actions and cannot be prosecuted for the offence in future.

Thaiday is currently subject to a treatment order at a high-security ward in Park Centre for Mental Health on Brisbane’s outskirts.

It is unclear if she will ever be released back into the community.

Before the killings, she had no previous criminal history and had never been treated for mental health issues, the court heard.

Thaiday sat silently in the dock and showed little emotion while details of the case were read out in court.

She stared ahead for most of the proceedings, although briefly acknowledged her adult son Lewis, who found his dead siblings and his mother with self-inflicted stab wounds.

Mother’s actions ‘shockingly out of character’

Three psychiatrists said it was likely Thaiday’s mental state had been deteriorating for months, and in the days leading up to the killings, she believed she could communicate with spirits, threw items from the house into the front yard, and was walking up and down the street yelling.

When Thaiday finally acted with violence, she was not under the influence of drugs, alcohol or any other substance, the psychiatrists said.

Thaiday, pictured shortly after giving birth in the back of an ambulance, date unknown.

Psychiatrist Dr Pamela van de Hoef said Thaiday was driven by “unshakable false beliefs” and her actions were “shockingly out of character”.

“She believed at the time, and for some days and weeks before that, that the end of the world was coming,” she said.

Another psychiatrist, Dr Jane Phillips, said Thaiday suffered a severe schizophrenic psychosis.

“She heard the sound of a bird … and believed that was a message that she must kill her children in order to save them,” she told the court.

Killings were ‘schizophrenia at its worst’

Justice Jean Dalton said the defence case for insanity was made based on “a very convincing body of evidence”.

“Ms Thaiday had a mental illness that deprived her of capacity at the time of the killing,” Justice Dalton said.

“That is, that she’s entitled to the defence of unsoundness of mind — there’s just no doubt about that on the evidence, and there’s no doubt about the legal conclusion that flows from that.”

Dr Frank Varghese, one of two psychiatrists assisting Justice Dalton, said Thaiday’s “apocalyptic delusional state” was one of the worst cases of schizophrenia he had ever seen.

He said it may have been triggered by Thaiday’s long-term cannabis usage, which only stopped months before the killings.

“This is schizophrenia at its very depth and its worst in terms of the terror for the patient, as well as the consequences for the individuals killed,” he said.

Justice Dalton allowed Thaiday escorted leave on the grounds of The Park centre, with psychiatrists believing it could help with her treatment.

– ABC