Mahkamah Persekutuan telah memutuskan seperti berikut: “(1) When the defence of insanity was raised, there was a two-stage process before the defence of legal insanity was available to an accused. Firstly, there must be a finding that the accused was medically insane at the time when he committed the alleged offence. This was based on a medical evaluation and lay with the medical expert to determine. This was not conclusive to qualify the accused as being legally insane. To determine whether the accused was legally insane, one must proceed to the second stage, namely, whether the accused, by reason of his psychiatric condition, had lost his cognitive faculties to a degree that he was incapable of knowing the nature of his act or that what he was doing was wrong or contrary to law. This stage was for the Court to determine from the evidence adduced at trial. This was in line with the ingredients listed under s 84 of the Code. (para 46) The trial Judge found that the prosecution's witnesses themselves indicated that the accused had mental health problems due to substance abuse, and this was held by the trial Judge as sufficient to establish a defence under s 85(2)(b) of the Code. However, the trial Judge failed to give a sufficient judicial appreciation of the facts to support the said defence, which led to serious misdirection. In the present appeal, there was no scientific evidence to support the contention that the respondent was intoxicated, having considered his conduct before and after the commission of the crime from the testimony of the appellant's witnesses. As the defence was not called, there was no evidence from the respondent to show that by reason of the drug intoxication, he was temporarily insane at the time he committed the offence. (paras 59 & 64) In acquitting the respondent at the end of the prosecution's case, the trial Judge and the panel of Judges in the Court of Appeal had clearly made numerous erroneous determinations. Firstly, it was certainly a flaw to support the finding of insanity that qualified as a defence under s 84 of the Code by the two Courts below based on the opinion of a police officer who was familiar with the accused, while rejecting the medical evidence of the forensic consultant in psychiatry in Hospital Bahagia, Ulu Kinta. Secondly, after having found that the appellant had established a prima facie case as charged, it was incumbent for the trial Judge to call for the respondent to enter his defence. It was premature for the trial Judge to acquit the respondent at the end of the prosecution's case solely based on medical evidence, as that was not a complete defence in law as envisaged under s 84 or s 85(2)(b) of the Code. The trial Judge should have continued with the trial and heard the defence's version. It was certainly premature for the trial Judge at the end of the prosecution's case to determine whether or not the respondent was of unsound mind when he committed the offence, as the onus of proving the defence on a balance of probabilities was on the respondent at the defence stage of the trial. Having found that the offence of murder had been established by the prosecution, it was incumbent upon the trial Judge to direct the respondent to state his defence. By failing to do so, the trial Judge had fallen into a serious error of law, repeated by the Court of Appeal, which warranted appellate intervention. (paras 65-67) The Court of Appeal erred when it chose not to follow PP v. Lim Poo Teck, which established that acquittals should not occur prematurely solely based on medical testimony without hearing the defence. Legal insanity had to be proven by the defence before the defence of insanity under s 84 of the Code applied. Acquitting the respondent before defence was called was acquitting the respondent before the defence of legal insanity (be it under s 84 or s 85(2) (b) of the Code) was proven, which was a serious error of law. (para 73).” (penekanan diberikan)