'I did a terrible thing', Queenie's killer
Qianqian "Queenie" Xu spent just two months in the world before her schizophrenic grandfather fatally plunged a knife into her stomach, his mind overrun with a delusion that his wife and daughter were trying to kill him.
Yonghou Cao, 54, killed his two-month-old granddaughter and stabbed the two women while staying with his daughter in Brisbane on a visit from China in 2016, later admitting "I did a terrible thing".
Cao had been charged with one count of murder and two counts of attempted murder but the charges were dropped last month by the Mental Health Court, which ruled he was of unsound mind.
It can now be revealed the attack began after the Chinese man's wife, Huijuan Fu, slapped him upon discovering he had not taken his antipsychotic medication for two months.
He punched and kicked her and she grabbed a kitchen knife to protect herself and stop him from assaulting her again.
But the sight of the knife had the opposite effect on Cao, who was suffering with a paranoid delusion that his wife and daughter Yuanyuan were trying to kill him.
He grabbed another knife and stabbed his wife in the chest and shoulders and repeatedly stabbed Yuanyuan, who ran out of the house in suburban Parkinson to get help.
His wife reported she slipped and fell to the floor, waking Queenie, and said she saw Cao walking towards the baby's cot with the knife before she passed out.
After fatally stabbing Queenie in the abdomen, Cao turned the knife on himself.
He initially told psychiatrists he had acted in self-defence, but after more than a year of treatment at a Brisbane psychiatric hospital, acknowledged it was his fault and Queenie did not deserve to die.
"The baby was innocent. I did a terrible thing. I don't want to talk about it," he told his psychiatrist in August last year.
The Mental Health Court published the reasons for its decision on Thursday, including that psychiatrists had concluded he was "floridly psychotic" at the time of the attack and was not in control of his actions.
Cao told his psychiatrists he heard a rumbling noise in his head all the time that he believed was telling him to kill and interpreted the numbers on his daughter's numberplate to be a signal she wanted to kill him.
The court heard Cao's condition improved during the course of his treatment but he remained a risk to the public.
Justice Jean Dalton placed Cao on a forensic order, meaning he will continue to be detained for involuntary treatment.
She also granted an order sought by his daughter, that he not be allowed to contact her.