By Boo Kok Chuon

Yesterday’s news from Bandar Utama was heartbreaking.

As a parent, few things are more terrifying than sending your child to school and never seeing your child come home. Yap Shing Xuen was 16. She died in a place where every parent should be entitled to believe his or her child is safe. Whatever legal discussion follows, that human tragedy must remain at the centre of this case.

I was devastated by the decision.

But on a very different, and obviously much lesser, level, I was devastated for a second reason too. For some time I had been developing a proposition about plea bargaining in homicide cases. I still think the concern behind it was real.

The solution I attached to it is finished.

The proposition

My concern began with Singapore’s River Valley High School killing.

On 19 July 2021, a 16-year-old Secondary 4 student killed Ethan Hun Zhe Kai, a 13-year-old Secondary 1 student, in a school toilet with an axe. He had initially been charged with murder. The Prosecution later accepted that his major depressive disorder entitled him to the partial defence of diminished responsibility under Exception 7 to section 300 of the Penal Code. The charge was reduced to culpable homicide not amounting to murder. He pleaded guilty and was sentenced to 16 years’ imprisonment.

The admitted facts showed months of preparation. He researched and bought an axe, sharpened it, kept photographs of the school floor plan on his phone, and watched videos of actual killings to learn how to kill more efficiently. The sentencing judge described a “chilling degree of premeditation and cold logic”, a description later adopted by the Court of Appeal in CNK v Public Prosecutor [2024] SGCA 42.

My discomfort was never that diminished responsibility should not exist. It was institutional.

Where a murder charge has already been brought, particularly in a case of exceptional public importance, should the Prosecution be able to reduce that charge, followed by a guilty plea, without the central question of criminal responsibility ever being tested at trial?

CNK itself explains the mechanism. Where the Prosecution has considered the psychiatric reports, accepts that diminished responsibility applies and proceeds on a reduced charge, the court does not have to determine for itself whether Exception 7 is made out. It proceeds on the basis that it applies.

My tentative answer was no. I thought that, at least for the gravest cases, there should be some form of judicial control over the reduction. Perhaps leave of court. Let the experts testify, let their evidence be cross-examined, and let the court decide.

I knew Article 35(8) of our Constitution, which vests prosecutorial discretion in the Attorney-General, posed a serious constitutional obstacle. I thought that was the weakness I needed to solve.

It was not.

The real weakness was a sentence I kept relying on without properly examining it: if murder is not ultimately established but a lesser homicide offence is, the court can deal with the lesser offence.

That sentence was doing an enormous amount of unexamined work.

The cliff edge

Considered on its own, diminished responsibility has a floor. If Exception 7 fails, the murder charge stands. If it succeeds, the charge is reduced to culpable homicide not amounting to murder. The Court of Appeal confirmed precisely that in CNK.

A complete defence has no such floor.

Singapore has its own complete defence of unsoundness of mind under section 84. Our 2019 criminal law reforms added a third, volitional limb to the traditional cognitive limbs. A person may also fall within section 84 where, by reason of unsoundness of mind, he is completely deprived of any power to control his actions.

The cliff edge was therefore already sitting in our own Penal Code. Bandar Utama did not create it.

It simply made me look at it.

“Nothing is an offence”

The factual resemblance between Bandar Utama and River Valley is difficult to ignore.

On 14 October 2025, a 14-year-old student killed a 16-year-old schoolmate in the girls’ toilet of a secondary school in Bandar Utama. Police said the following day that the knives and kerambit seized from him had been bought online some time earlier. He was subsequently charged with murder under section 302 of the Malaysian Penal Code.

The matter went to trial in the Shah Alam High Court before Judge Adlin Abdul Majid. Because the accused was a minor, the proceedings were conducted in camera. The court found that the Prosecution had established a prima facie case and called on him to enter his defence. The defence then called the accused and a forensic psychiatrist from Hospital Bahagia Ulu Kinta.

Then the defence succeeded under section 84 of Malaysia’s Penal Code.

Its opening words are extraordinarily powerful:

“Nothing is an offence which is done by a person who, at the time of doing it, by reason of unsoundness of mind…”

Nothing is an offence.

Not murder reduced to culpable homicide. Not a mitigating factor to be reflected at sentencing.

Nothing is an offence.

On 14 September 2026, the High Court acquitted the accused, by then 15, on the ground of unsoundness of mind and ordered him placed at Hospital Bahagia Ulu Kinta for a period to be approved by the Sultan of Selangor. Because the proceedings were closed and no written grounds appear to be publicly available as at the time of writing, the detailed psychiatric evidence is known mainly through reporting and counsel’s account outside court. According to that account, the psychiatrist diagnosed severe schizophrenia; the accused believed himself to be God and said he heard voices and instructions.

He did not simply walk free. Malaysia’s Criminal Procedure Code requires an insanity acquittal to state specifically whether the accused committed the physical act. Where the finding is that he did, and the act would otherwise have constituted an offence, the Code provides for safe custody and allows the Ruler to order confinement in a psychiatric hospital during the Ruler’s pleasure. There is also a statutory process by which discharge may eventually be considered if the relevant medical authorities certify that it can safely occur.

So there is a finding that he committed the act, and there is detention. But there is no conviction for homicide, nor any lesser homicide conviction sitting beneath section 84 waiting to catch the case.

Singapore added diminished responsibility as Exception 7 to section 300 in 1961. Malaysia has no equivalent intermediate defence in its section 300. The landing that Singapore reached in River Valley was therefore not available in the same form in Shah Alam.

This was the risk I had failed to account for. I had assumed that adjudication merely shifted the decision on the level of criminal responsibility from the parties to the court.

Section 84 exposes the flaw.

Sometimes the judicial answer is no criminal responsibility at all.

What we cannot know

It is tempting to ask whether the River Valley accused might have succeeded under section 84 had the murder charge gone to trial.

I do not think that speculation takes us very far.

The psychiatric evidence later recorded in CNK points strongly away from such an outcome. The Court of Appeal recorded that his MDD did not affect his understanding of right and wrong or his ability to control his actions. It also noted that, despite his illness, he retained significant rationality.

But there was no murder trial on section 84. A trial could have produced further reports, cross-examination and findings that never existed in the guilty-plea case.

We do not know what would have happened.

We never will.

More importantly, my proposition does not depend on that counterfactual. The risk is not that River Valley itself would necessarily have ended differently. It is that another homicide case, with different psychiatric evidence, may.

Bandar Utama has now shown what that possibility looks like.

What public interest are we trying to serve?

This brings me back to why I developed the proposition in the first place. I thought greater judicial scrutiny served the public interest.

There is public value in having psychiatric evidence tested in court. Bandar Utama produced something River Valley did not: a judicial determination that the accused’s mental condition crossed the threshold of a complete defence.

But what is that knowledge worth?

Yap Shing Xuen’s mother, Wong Lee Ping, has said publicly that she will continue seeking justice for her daughter.

The doctrinal answer is that once section 84 is made out, retribution is not merely reduced. Its premise, criminal culpability, is legally absent. Punishment cannot simply be calibrated downward as though section 84 were another mitigating consideration.

That may be legally coherent. It offers little answer to the separate human demand for vindication.

Usually, a conviction does two things at once. It punishes an offender and it publicly declares that a legal wrong was committed against the victim. Here those functions came apart. Malaysian law still requires the court to state whether the accused committed the physical act, but whether that finding provides the same sense of vindication is a different question.

My earlier proposal was itself an attempt to serve public interest. I wanted serious questions of criminal responsibility to be tested, not simply resolved by a charging decision followed by a guilty plea.

Bandar Utama forces me to ask what price I was prepared to pay for that.

Should a system favour adjudication, with psychiatric evidence tested before a court, even where doing so exposes the prosecution to the possibility of a complete defence? Or, where the law permits an appropriate lesser homicide charge, should prosecutorial discretion remain broad enough to secure criminal responsibility even though the central psychiatric question may never be fully adjudicated?

Published prosecutorial reasons do not solve this. They may improve transparency, but what I wanted was tested reasons. Those are not the same thing.

Tested reasons come with the possibility that the defence succeeds. One cannot ask a court to decide a question while reserving the right to reject one of the legally available answers.

That is the part I had not properly confronted.

I still believe my original concern about plea bargaining was real. I no longer believe my proposed solution was.

Bandar Utama has shown me that the safeguard I thought would solve one public-interest problem creates another.

I do not yet know what should replace it.