KUALA LUMPUR: The teen in the Bandar Utama school stabbing incident had been harbouring feelings for the 16-year-old victim for more than a year before fatefully causing her death.
His infatuation with the deceased, however, evolved into envy, anger and hatred, and an intention to kill her.
High Court judge Justice Adlin Abdul Majid said this in her full grounds of judgment in the case made available on Wednesday (Sept 23).
In her judgment, she said the court had largely accepted the unchallenged findings of court-appointed consultant forensic psychiatrist Dr Ian Lloyd Anthony, who testified as a defence witness at the trial.
Dr Anthony's findings were set out in a 27-page psychiatric report which detailed the teen's mental condition.
"From around August 2024, the teen developed an infatuation with the deceased. He began physically observing and following her at school, and separately created social media accounts to follow her online.
"Over the following year, this infatuation evolved. First, he was convinced that the deceased reciprocated his feelings and was in love with him - a condition the report referred to as an erotomanic delusion," Justice Adlin said.
After watching an online video on the murder of a British teacher in Japan, the teen's infatuation with the deceased evolved into envy, anger and hatred, and an intention to kill her.
"From March 2025, the teen began to experience auditory hallucinations in the form of a voice which he attributed to Dylan Klebold (Columbine High School mass murderer), speaking to him in Mandarin, which he described as instructing him to kill the deceased.
"The report referred to this as commanding auditory hallucinations. He also began, from around this period, to identify with the character of a god-like vigilante from Japanese anime.
"The teen began to believe that he had himself become a god-like figure entitled to eliminate those he considered unworthy, a condition that the report referred to as grandiose delusions.
"It was around this time that the teen purchased the Death Note Notebook, in which he wrote four names of his schoolmates, including the deceased," Justice Adlin said.
On Oct 14, 2025, the teen entered the female washroom at the school armed with knives and confronted the deceased at knifepoint before stabbing her repeatedly, stopping only when overcome by the smell of blood.
He then left the washroom and proceeded to a square at the school where he discarded his weapons, except for the knife. He was then disarmed by his brother.
"Taken as a whole, I accept that this chronology reflects a serious and longstanding psychotic illness that developed and worsened progressively over several years.
"By the time of the incident, the teen was in the grip of an active psychosis, marked by delusions directed at the deceased and a commanding hallucinated voice instructing him to kill her," Justice Adlin said.
Post-incident, the teen was remanded and later admitted to Hospital Bahagia Ulu Kinta on Oct 22, 2025, where he was under the care of Dr Anthony.
Dr Anthony testified that within three weeks of starting antipsychotic medication, the teen's hallucinations ceased and the delusions began to dissolve, and he began engaging warmly with his family in a manner not seen for years.
The teen was diagnosed with schizophrenia of very early onset (before the age of 13) with psychopathic and sadistic traits and Dr Anthony opined that the illness was severe enough to incapacitate him from appreciating that his act was wrong or against the law.
Justice Adlin said the court found that on the balance of probabilities, at the time of the incident, the teen had suffered schizophrenia, which was a disease of the mind, and therefore of unsound mind.
"Following the findings as set out, pursuant to Section 84 of the Penal Code, read together with Section 347 of the Criminal Procedure Code, the court acquits the teen of the charge under Section 302 of the Penal Code, on the ground of unsoundness of mind," she said in the decision.
On Sept 14, the High Court acquitted the teen of murder and ordered the boy to be detained and treated at Hospital Bahagia Ulu Kinta in Perak at the pleasure of the Sultan of Selangor.
