that he is doing what is either wrong or contrary to law. [20] Two limbs entitle him to an acquittal. First, if at the time of doing the act, by reason of unsoundness of mind, he did not know the nature of the act, or if he knew the nature of the act did not know that it was either wrong or contrary to law (Criminal Law in Singapore and Malaysia Text and Materials by KL Koh, CMV Clarkson and NA Morgan). For purposes of this appeal, the crucial time of having an unsound mind therefore is at the time of the brutal attack, and not before or after the act (John Dawlat Moon [1927] 29 Cr LJ 393); [1928] AIR (P) 363). A plea of unsoundness of mind at the time of trial will not avail an accused person (Nota Ram [1866] PR No 56 of 1866; The Law of Crimes by Ratanlal, p. 165). Regardless of the other relevant prerequisites of s. 84, it is incontrovertible that unless this preliminary factor of unsoundness of mind is established first, this defence cannot prevail. S/N dikT0XScB02ALrzdtffSkA [21] It is established law that the burden of proof lies on the Appellant that is if he wishes the court to believe that he was of unsound mind at the time when he committed the offence. Needless to say, this defence of unsound mind needs to be established at the earliest possible moment ie, at the prosecution's stage. This is to avoid any allegation of afterthought. [22] Under s. 105 of the Evidence Act, the legal burden is on the Appellant to establish the fact that he committed the act in a moment of unsound mind (Jayasena v. R [1970] 1 All ER 219). In an English case, Woolmington v. DPP [1935] AC 462) the court reiterated that for a defence of insanity, the legal burden of proof on the balance of probability, is placed on an accused person.” [90] Di dalam kes PP v. Shalima Bi [2016] 1 MLJ 799, Mahkamah Rayuan melalui penghakiman yang disampaikan oleh Abdul Rahman Sebli HMR (beliau pada ketika itu) menyatakan seperti yang berikut: “[53] What a trial judge has to do as the first step in determining whether the defence of insanity has been established is to see whether the accused was medically insane at the time he committed the act. Expert medical evidence is necessary as the question of whether he was medically insane at any particular point in time is in the realm of forensic science. It is not something that the court can determine without the benefit of expert opinion. [54] Once that threshold is crossed, the next step is for the trial judge to consider whether, by reason of medical insanity, the accused was incapable of knowing the nature of his act or that what he was doing was either wrong or contrary to law. Expert medical opinion is S/N dikT0XScB02ALrzdtffSkA irrelevant as the question of whether the accused was incapable of knowing the nature of his act or that he was doing what was either wrong or contrary to law is a matter to be inferred from the proved facts and circumstances and not from expert medical opinion. It is purely a question of fact for the trial judge to determine." [91] Di dalam kes PP v. Jufri Nanti [2016] CLJU 53; [2016] 1 LNS 53 Mahkamah Rayuan melalui penghakiman yang disampaikan oleh Abang Iskandar Abang Hashim HMR (beliau pada ketika itu) menyatakan seperti yang berikut: “[35] So it was clear to our mind, that in determining whether an act could be categorised as one that has amounted to an act of insanity under section 84 of the Penal Code, it would inevitably involve a two-tier exercise. First, there must be finding, based entirely on medical evaluation by a psychiatrist that the accused person was suffering from some kind of psychiatric condition that was affecting his cognitive faculties at the material time. This condition may take a variety of forms as medically described, such as he being delusional and so forth. That condition may qualify a person as being medically insane. But that finding per se is not sufficient to be determinate or conclusive of the fact that the accused person is legally insane, a condition with which section 84 of the Penal Code is concerned about as a general defence under the law. To be legally insane, as opposed to being merely medically insane, the person must be determined by the psychiatrist to have lost his cognitive faculties to a degree such that he is incapable of knowing the nature of his act, or that what he is doing is wrong or contrary to law. If the first-tier test is a medical test, then this second-tier test is a legal test. S/N dikT0XScB02ALrzdtffSkA Learned Justice Ariffin Zakaria JCA [as he then was] described the defence of insanity under section 84 of the Penal Code in the following manner: It is settled law that the defence of insanity under section 84 is concerned with the accused's legal responsibility at the time of the alleged offence and not with whether he was medically insane at that time. See Pendakwa Raya v. Zainal Abidin bin Mat Zaid [1993] 1 CLJ 147; PP v. Misbah [1998] 1 CLJ 759; [1997] 3 MLJ 495. Indeed, the learned authors of Ratanlal and Dhirajlal's Law of Crime, 5th Edn. at page 289 had written when the Court is faced with a defence of insanity under section 84 of the Penal Code, it would have to consider two matters, namely: [i] whether the accused person has successfully established, as a preliminary issue, that at the time of committing the act he was of unsound mind, and [ii] if he was of unsound mind, whether he has proven that his unsoundness of mind was of a degree to satisfy one of the tests earlier mentioned i.e., that the accused was incapable of knowing the nature of his act as being wrong or against the law.” [92] Di dalam kes PP v. Ismail bin Ibrahim [1998] 3 MLJ 243, Mahkamah memutuskan seperti yang berikut: “(iii) that the onus of proving insanity is on the accused under s 105 of the Evidence Act 1950. It will therefore be observed that s 84 embodies the fundamental maxim of criminal law, that is to say, an act done does not constitute a crime unless done with a guilty intention. Thus, where a plea under this section has been successfully raised, the effect is that there is no culpability on the S/N dikT0XScB02ALrzdtffSkA part of the accused as he did not have the required mens rea at the time of committing the alleged act. It follows that the question of the guilt of the accused does not arise as he cannot be said to have committed any offence. Therefore, the law requires that an order of acquittal must be made with regard to the charge preferred against him. The court is only required to make a finding whether he committed the act or not." [93] Di dalam kes Tiong Ing Soon v. PP [2019] 7 CLJ 341, Mahkamah Rayuan melalui penghakiman yang disampaikan oleh Kamaludin Md Said HMR (beliau pada ketika itu) menyatakan seperti yang berikut: "[30] From the authorities, firstly, there must be a finding based upon medical evaluation that the accused was suffering from some kind of psychiatric condition that impaired his cognitive faculties at the material time so as to be classified as medically insane. This of course is a matter for a medical expert to determine. But is not conclusive. Secondly, in order to be legally insane, the accused must be determined by reason of that psychiatric condition to have lost his cognitive faculties to a degree such that he is incapable of knowing the nature of his act or that what he is doing is wrong or contrary to the law. This stage is for the court to determine from the evidence adduced during the trial. The defence of insanity under s. 84 of Penal Code is concerned with the accused's legal responsibility at the time of the alleged offence and not whether he was medically insane at that time (see: Pendakwa Raya v. Zainal Abidin Mohd Zaid [1993] 1 CLJ 147; PP v. Misbah Saat [1998] 1 CLJ 759; [1997] 3 MLJ 495). The burden is on the appellant to prove his insanity as required under s. 84 of the Penal Code and the standard S/N dikT0XScB02ALrzdtffSkA of proof is on a balance of probabilities (see: Goh Yoke v. PP [1969] CLJU 48; [1969] 1 LNS 48; [1970] 1 MLJ 63; Rajagopal v. PP [1976] CLJU 122; [1976] 1 LNS 122; [1977] 1 MLJ 6). (Emphasis included)." [94] Di dalam kes PP v. Lim Poo Teck [2023] CLJU 2518, [2023] 1 LNS 2518, Mahkamah Rayuan memutuskan seperti yang berikut: “In this context, it is pertinent to emphasise that at the prosecution stage, expert medical opinion assumed little value or significance as the question of whether the Respondent was incapable of knowing the nature of his act or that he was doing what was either wrong or contrary to law is a matter to be inferred from the proved facts and circumstances and not from expert medical opinion. Legal insanity is not for the medical witnesses to decide however eminent they may be. That onus is upon the defence and it is to satisfy the court on the balance of probabilities. It is purely a question of fact which rests upon substratum of oral evidence, the credibility of which is entirely for the learned trial judge to determine after the close of the defence's case with the aid of the medical evidence.” [95] Seterusnya, di dalam kes PP v. Mohd Rozani Yahaya [2025] 2 CLJ 21, Mahkamah Persekutuan melalui penghakiman yang disampaikan oieh Zabariah Mohd Yusof HMP telah menerangkan dengan jelas prinsip undang-undang berkaitan pembelaan tidak waras serta perbezaan di antara “legal insanity” dan “medical insanity” seperti yang berikut dan kami petik: S/N dikT0XScB02ALrzdtffSkA “The law on the defence of insanity - Medical Insanity and legal insanity: [37] Within the labyrinth of mental health and the legal system, stood the concepts of medical and legal insanity, which are distinct but interconnected in their realm. Undeniably, both the terms appear to share some common traits, as they deal with conditions affecting the human mind. However, each term serves different purposes and has varying implications for individuals in areas of medicine and in court proceedings. [38] It is important to be borne in mind of the distinct nature of these two terms, more so when the defence of insanity is raised in criminal proceedings, as it affects the ultimate order given by the court against the accused. [39] The term "medical insanity" refers to a disorder of the mind which covers a whole range of mental health conditions which may impair one's cognitive or emotional functions. It encompasses disorders such as anxiety, depression and other psychiatric conditions that may require medical attention and treatment. These conditions, however do not necessarily render one as legally insane under section 84 of the Penal Code, so as to accord a complete defence in criminal law when an offence has been committed. [40] In medical insanity, the emphasis is on one's mental health and wellbeing or psychological disorder, with the primary goal being the diagnosis, treatment and management of the mental disorder. It is a medical diagnosis based on one's mental health condition. Persons S/N dikT0XScB02ALrzdtffSkA experiencing medical insanity may still possess the capability to make informed decisions and can lead a life of normalcy with the appropriate medical intervention. Medical insanity is diagnosed by healthcare professionals premised on medical criteria and considerations, symptoms and the impact of mental illness on the individual's daily functions. The consequences of a finding of medical insanity will primarily lead to medical treatment, therapy and other interventions aimed at managing and improving the individual's mental health. Every person who is mentally ill is not, ipso facto, exempted from criminal responsibility. [41] Whereas, legal insanity involves a distinct set of criteria and considerations within the framework of the legal system. Unlike medical insanity, which involves a question of mental health only, legal insanity goes beyond mental health and pertains to one's legal capacity and responsibility for their actions. It involves a legal determination that a person, due to a severe mental disorder, is not criminally responsible for their actions. It is a legal status that affects the person's accountability to his actions in a court of law. This accords the rationale of legal insanity being a recognised defence in criminal law, as it implies that, at the time when committing an offence, the accused was found to be in a state of not understanding the nature and consequences of his/her actions. Legal insanity is determined by legal standards, which may vary by jurisdiction. It entails assessments by mental health experts and legal professionals to analyse and evaluate the accused's mental state at the time of the alleged offence committed. The consequences of legal insanity may result in the accused being declared not criminaliy S/N dikT0XScB02ALrzdtffSkA responsible or being committed to a psychiatric institution instead of facing traditional criminal penalties. [42] For the accused, to succeed on the defence of legal insanity, the accused must establish, often through psychiatric or psychological evaluations, that he/ she was not in control of his/ her reasoning during the commission of the offence. This defence is anchored in section 84 of the Penal Code, which outlines the conditions under which an accused can be considered legally insane. [43] The burden of proof for medical and legal insanity also differs. In legal insanity, the onus lies with the accused to prove his/ her mental state at the time when the offence was committed pursuant to section 105 of the Evidence Act 1950. This burden though significant is not as onerous as the prosecution to prove the accused's guilt. It is on a balance of probabilities and not merely to cast a reasonable doubt in the prosecution's case (see Rajagopal v. PP [1976] CLJU 122 and Goh Yoke v. PP [1969] CLJU 48) [44] To establish legal insanity, the accused must present a prima facie case, supported by reasonable materials. This involves presenting evidence of the accused's conduct, before, during and immediately after the commission of the alleged offence, corroborated with the relevant medical documentation. The purpose is to convince the court that due to the accused's mental capacity, the accused should be exempt from full criminal responsibility." S/N dikT0XScB02ALrzdtffSkA [96] Peguam tertuduh yang bijaksana menghujahkan bahawa Hakim Mahkamah Tinggi yang bijaksana telah terkhilaf kerana tidak menolak pandangan SP13 (Dr. Saramah bt Mohd Isa) Pakar Psikiatri Unit Psikiatri Forensik Hospital Bahagia, Ulu Kinta bila SP13 di dalam laporan perubatan forensik psikiatrinya (ekshibit P33) merumuskan seperti yang berikut: “23. Setelah meneliti segala maklumat serta daripada pemeriksaan dan pemerhatian yang telah dilakukan, saya berpendapat bahawa: