THE STATE OF WESTERN AUSTRALIA -v- MOUSSA [2026] WASC 355

[2026] WASC 355 Page 1 JURISDICTION : SUPREME COURT OF WESTERN AUSTRALIA IN CRIMINAL CITATION : THE STATE OF WESTERN AUSTRALIA -v- MOUSSA [No 3] [2026] WASC 355 CORAM : PALMER J HEARD : 1 MAY, 23 JULY AND 25 AUGUST 2026 DELIVERED : 25 AUGUST 2026 FILE NO/S : INS 24 of 2025 BETWEEN : THE STATE OF WESTERN AUSTRALIA Prosecution AND DAVID NADI LAMIE MOUSSA Accused Catchwords: Criminal Law (Mental Impairment) Act 2023 (WA) - Accused acquitted of charge on the grounds of mental impairment - Custody order with a limiting term of life imprisonment Legislation: Criminal Law (Mental Impairment Act 2023 (WA) Criminal Code (WA) Result: Custody order made with a limiting term of life -- 1 of 13 -- [2026] WASC 355 Page 2 Category: B Representation: Counsel: Prosecution : Ms K Jennings (1 May 2026 and 23 July 2026) Ms D Borkowski (25 August 2026) Accused : Ms A Fedele Solicitors: Prosecution : Director of Public Prosecutions (WA) Accused : Legal Aid (WA) Case(s) referred to in decision(s): The State of Western Australia v Chokolich [2024] WASC 346 The State of Western Australia v Moussa [2026] WASC 164 The State of Western Australia v Tekle [No 3] [2024] WASC 417 The State of Western Australia v Truong [2024] WASC 500 -- 2 of 13 -- [2026] WASC 355 PALMER J Page 3 PALMER J: Introduction 1 On 1 May 2026, I found Mr David Moussa not guilty of both the murder of his father and of an omission causing danger to his stepmother, on account of mental impairment pursuant to s 27(1) of the Criminal Code (WA) (Criminal Code).1 2 As I explained at the time, the Criminal Law (Mental Impairment) Act 2023 (WA) (the CLMI Act) now requires me to make an order in relation to Mr Moussa under pt 5 of that Act. 3 As the offence of murder is a serious offence, I must make a custody order unless I am satisfied, on the balance of probabilities, that any risk that Mr Moussa presents to the safety of the community can be adequately managed by a community supervision order. 4 The matter was adjourned to obtain reports to assist the consideration of the appropriate order to be made. 5 Two reports were subsequently obtained. One from Dr Adam Brett (who also gave evidence at the trial). The other from Dr Thamei Damoderam and Dr Greer Jalland at the State Forensic Mental Health Service. Neither report suggested that the risk to the safety of the community posed by Mr Moussa could be adequately managed by a community supervision order, at this time. 6 The State contended that a custody order should be made and Mr Moussa conceded that it was appropriate for such an order to be made. 7 In my view, Mr Moussa's concession was properly made. I am not satisfied on the evidence before me that it is more likely than not that the risk Mr Moussa presents to the safety of the community can be adequately managed under a community supervision order. Mr Moussa's current condition makes him a risk to others. 8 The CLMI Act also requires me to set a limiting term for the order. To do this, I am required to estimate the term of imprisonment that a court would have imposed if Mr Moussa had been convicted of the offences for which he has been convicted after pleading guilty at the 1 The State of Western Australia v Moussa [2026] WASC 164. -- 3 of 13 -- [2026] WASC 355 PALMER J Page 4 first available opportunity. In making this estimate I am obliged to ignore Mr Moussa's mental impairment. 9 In relation to the murder conviction, subject to the exceptional circumstances identified in s 279(4)(a) and s 279(4)(b) of the Criminal Code, the sentence of life imprisonment for murder is a mandatory sentence. 10 The State submitted that there were no exceptional circumstances in this case and Mr Moussa conceded as much. 11 In my view, if Mr Moussa had pleaded guilty to the charge of murder, and the court sentencing him did not take into account his mental impairment, he would have received a sentence of life imprisonment. I do not consider that the exceptional circumstances identified in s 279(4)(a) and s 279(4)(b) are present in this case and I consider that if Mr Moussa had been criminally responsible, the seriousness of his offending would have required a life term of imprisonment. 12 I will therefore set the limiting term of Mr Moussa's custody order as the duration of his life. 13 I set out my reasons for these conclusions below. Does pt 5 of the CLMI Act require two orders to be made? 14 As Mr Moussa has been convicted of more than one offence, an initial question which arises is whether pt 5 of the CLMI Act requires a single order to be made, or whether separate orders are required for each offence. 15 This issue was considered by the Chief Justice in The State of Western Australia v Smith,2 where the Chief Justice expressed the preliminary view that pt 5 requires a single order to be made. The Chief Justice explained his reasons for this conclusion as follows:3 Limiting terms in the case of multiple charges Historically, under the relevant provisions of the Criminal Code and the repealed Act, persons found to be unfit to stand trial in relation to a number of charges, or who had been acquitted on account of unsoundness of mind of multiple charges, were often made subject to a 2 The State of Western Australia v Smith [2024] WASC 361 (Smith). 3 Smith [21] - [29]. -- 4 of 13 -- [2026] WASC 355 PALMER J Page 5 single custody order. As all custody orders under those former statutory regimes operated as a form of 'Governor's pleasure' detention, in which the custody order could not otherwise expire by operation of law, to have been subject to more than one such order, simultaneously, could have made no practical difference to the person's liberty. While it does not arise in the present case, it would appear to be at least theoretically possible for a person to be subject to more than one custody order under the CLMI Act. That might arise, for example, where a person already subject to a custody order is charged with an offence committed during the custody order (either in custody or during a leave of absence) but is found unfit to stand trial on the subsequent charge. In such a case, unlike under the former statutory regimes, there may be a real practical difference between the different custody orders because each order could potentially have different limiting terms (and so might expire by operation of s 51(a) of the CLMI Act at different times). Nevertheless, the CLMI Act generally proceeds upon the assumption that a person subject to pt 6 of the Act will only be subject to one custody order. Certainly, the provisions in relation to places of custody and review of orders by the Mental Impairment Review Tribunal (Tribunal), in div 3 and 4 of pt 6 appear to proceed upon that basis. In addition, my provisional view is that, in circumstances in which a court is dealing with two or more charges against a person and is required to deal with the person under pt 5 of the CLMI Act the Court must make one order in relation to the person. I am of that view for the following reasons. First, it is clear that a court dealing with a person under the CLMI Act may do so in relation to two or more charges in a single prosecution notice or indictment, and at a single special proceeding (in the case of an accused who is not fit to stand trial) or trial (in the case of an accused who raises a defence under s 27 of the Criminal Code). In that regard, s 14 of the CLMI Act expressly provides that the Criminal Procedure Act 2004 (WA) (Criminal Procedure Act) applies to proceedings under pt 3 and pt 5 of the CLMI Act, with necessary modifications. The provisions of the Criminal Procedure Act in relation to matters such as joinder of charges would therefore apply to such proceedings. Secondly, where a court must make an order under pt 5, in relation to a person who is either unfit or has been acquitted on account of mental impairment, s 46 of the CLMI Act provides: (1) If a court must make an order under this Part in respect of an accused, it must – (a) make a custody order; or -- 5 of 13 -- [2026] WASC 355 PALMER J Page 6 (b) make a community supervision order; or (c) order that the person be released unconditionally. Section 46 is clear (by the repeated use of the word 'or') that the court may only make one order 'in respect of an accused' (not, I would observe, 'in respect of a charge'). For example, a court could not make a custody order and a community supervision order in relation to an accused. Indeed, the CLMI Act generally does not contemplate that a custody order and a community supervision order can apply to a person at the same time (see, for example, s 89, which requires the court to cancel a community supervision order if it makes a custody order in relation to a person on a community supervision order). Even more obviously it would be logically impossible for a court to make either a custody order or a community supervision order (under (s 46(1)(a) or (b)) and at the same time make an order 'that the person be released unconditionally' (s 46(1)(c)). Accordingly, in my view, where a court is dealing with a person on two or more charges in a prosecution notice or indictment and concludes that a custody order in respect of an accused is the appropriate order under pt 5, the court must make only one custody order (and not a separate order with respect to each charge). I have expressed this as a provisional view because, in the present case, I am not required to make a custody order but rather to set a limiting term for an existing custody order. 16 The Chief Justice's preliminary view was accepted and followed by Forrester J in The State of Western Australia v Tekle [No 3]4 and Lemonis J (as he then was) in The State of Western Australia v Truong.5 17 I respectfully agree with the Chief Justice's reasoning and gratefully adopt that reasoning. I will proceed on the basis that a single order is to be made. Should a custody order be made? 18 Section 46(1) and s 46(2)(a) of the CLMI Act provide that, as the offence of murder is a serious offence, I must make a custody order unless I am satisfied on the balance of probabilities that any risk that Mr Moussa appears to present to the safety of the community can be adequately managed under a community supervision order. 4 The State of Western Australia v Tekle [No 3] [2024] WASC 417 [14]. 5 The State of Western Australia v Truong [2024] WASC 500 [22]. -- 6 of 13 -- [2026] WASC 355 PALMER J Page 7 19 As I have mentioned, Dr Brett prepared a report after my verdict. For the purposes of preparing that report Dr Brett interviewed Mr Moussa by video link on 22 June 2026. 20 Dr Brett diagnosed Mr Moussa as suffering from chronic paranoid schizophrenia. 21 Dr Brett considered that Mr Moussa's functioning had improved significantly from the time when he committed the offences, but he thought that Mr Moussa had not returned to his previous levels of functioning. 22 Dr Brett said that Mr Moussa denied suffering from any psychotic phenomena but his clinical impression was that these were ongoing. He thought that Mr Moussa might be minimising his symptoms. 23 Dr Brett expressed an optimistic view about Mr Moussa's prognosis and thought that with appropriate treatment, the Mental Impaired Review Tribunal might be able to transition him into the community. 24 After he prepared his report, Dr Brett clarified that he did not consider that the risk presently posed by Mr Moussa could be managed in the community. He did not support the making of a community supervision order. 25 As I have also mentioned, I have also been provided with a report prepared by Dr Thamei Damoderam and Dr Greer Jalland from the State Forensic Mental Health Service. 26 Dr Damoderam and Dr Jalland, interviewed Mr Moussa at Hakea Prison on 4 June 2026 for 70 minutes. 27 Dr Damoderam and Dr Jalland considered that when they interviewed Mr Moussa he continued to have active, severe symptoms (which required the dosage of his medication to be increased). They said that he continued to suffer from psychosis and had significant auditory hallucinations of a commanding nature. 28 They considered that if he was released to the community on a Community Supervision Order without all necessary supports in place, he would be highly likely to relapse or reoffend as he is not currently well established on optimal treatment evidenced by ongoing psychosis. -- 7 of 13 -- [2026] WASC 355 PALMER J Page 8 29 They said that Mr Moussa required another hospital admission and a period of inpatient treatment to optimise his treatment regime. They said that he is in early stages of achieving some recovery, but his symptoms still are pronounced. 30 They said that Mr Moussa only had a superficial understanding of his mental illness, and the support needed for further recovery and rehabilitation. They said that he was able to identify that he was unwell during the incident involving his father, and that medications have helped reduce symptoms of psychosis. They said that he felt that he was well enough to be released from prison on a community supervision order, despite having recent adjustment to treatment and ongoing psychotic symptoms. They thought that this revealed that he was in the early stages of recovery. 31 They diagnosed Mr Moussa as suffering from schizophrenia. 32 They assessed Mr Moussa's risk of violence using the framework of the HCR20v3. They explained that this is an internationally validated structured risk judgement tool which identifies risk factors known to be associated with violent offending at a population level. 33 They said that Mr Moussa tested positive for three of the ten historical (static) risk factors associated with increased risk of violence: (a) violence (history of committing a murder); (b) substance use (history of using multiple substances); and (c) major mental disorder (diagnosis of schizophrenia). 34 They said that Mr Moussa tested partially positive for three more historical (static) risk factors: (a) relationships; (b) employment; and (c) treatment or supervision response. 35 They said that Mr Moussa tested partially positive for four of the five clinical risk factors: (a) insight; (b) violent ideation/intent; -- 8 of 13 -- [2026] WASC 355 PALMER J Page 9 (c) symptoms of major mental disorder; and (d) treatment and supervision response. 36 They said that Mr Moussa tested positive for three of the five future risk management factors: (a) professional services/plans; (b) living situation; and (c) personal supports. 37 They said that Mr Moussa was a moderate risk of future violence, with the risks increasing exponentially to high, should he be transitioned directly to the community. 38 They said that Mr Moussa is at high risk of offending if his mental illness is untreated and if he relapsed into substance use. They considered that he requires ongoing observation and stabilisation to manage and fully appreciate his risk profile. 39 They said that he needs scaffolding, further observation, medication optimisation, and adequate community supports to be established, with prosocial supports to avoid social isolation and potential medication non-adherence. 40 The State submitted that in light of the evidence, a custody order should be made. Mr Moussa conceded that such an order should be made. 41 In my view, Mr Moussa's concession was properly made. Mr Moussa's current condition makes him a risk to others. I am not satisfied on the evidence before me that it is more likely than not that the risk he poses to the safety of the community can be adequately managed by a community supervision order. For this reason, I made a custody order. What should the limiting term be? 42 When making a custody order, s 50 of the CLMI Act requires me to set a limiting term for the custody order as follows: (2) If a court makes a custody order, the court must set a limiting term for the order, being the best estimate of the term of -- 9 of 13 -- [2026] WASC 355 PALMER J Page 10 imprisonment or term of detention that the court would, in all the circumstances, have imposed if - (a) the court were sentencing the person for the offence; and (b) any mental impairment of the person were not taken into account. (3) For the purposes of subsection (2), the court must assume that — (a) the person had pleaded guilty to the charge at the earliest opportunity; and (b) there is no other option but to impose a term of imprisonment or term of detention. (4) The limiting term commences on the day on which the order is made unless the court, after taking into account any time that the person has already spent in custody in relation to the offence, orders that the term be taken to have commenced on an earlier day. 43 The penalty for the offence of murder is contained in s 279(4) of the Criminal Code which states as follows: (4) A person, other than a child, who is guilty of murder must be sentenced to life imprisonment unless — (a) that sentence would be clearly unjust given the circumstances of the offence and the person; and (b) the person is unlikely to be a threat to the safety of the community when released from imprisonment, in which case, subject to subsection (5A), the person is liable to imprisonment for 20 years. 44 The requirements of s 50 of the CLMI Act in the context of the offence of murder were considered by Quinlan CJ in The State of Western Australia v Chokolich.6 I respectfully adopt and apply the principles set out by the Chief Justice which may relevantly be summarised as follows:7 (a) that I am required to determine the 'best estimate' of the term of imprisonment that a court 'would, in all the circumstances' have 6 The State of Western Australia v Chokolich [2024] WASC 346 (Chokolich). 7 Chokolich [60] - [99]. -- 10 of 13 -- [2026] WASC 355 PALMER J Page 11 imposed based on certain assumptions. This task is necessarily a hypothetical exercise;8 (b) the use of the word 'would' signifies that I am required to 'stand in the shoes' of a hypothetical sentencing court and apply the relevant principles contained in the Sentencing Act 1995 (WA), including in s 6 of that Act, in light of ordinary sentencing principles;9 (c) one of the assumptions imposed by s 50 of the CLMI Act is that in setting the limiting term, I am not to take into account Mr Moussa's mental impairment. That assumption may be relevant to the circumstances of the offence, mitigatory factors and potential facts that might have resulted in a longer term of imprisonment;10 (d) the other assumptions imposed by s 50 of the CLMI Act are that I must assume that Mr Moussa has pleaded guilty to the charge of murder at the earliest opportunity.11 I must also assume that there is no other option but to impose a term of imprisonment; (e) subject to the exceptional circumstances identified in s 279(4)(a) and s 279(4)(b) of the Criminal Code, the sentence of life imprisonment for murder is a mandatory sentence. Therefore, on its proper construction, s 50 of the CLMI Act requires that if, on the assumptions required by that section, the mandatory term of life imprisonment would have been imposed, then the limiting term must be set as the duration of that mandatory term;12 (f) given the exceptional nature of a sentence other than life imprisonment for murder generally, the circumstances in which a limiting term on a charge of murder will be set as a term other than the duration of the person's life will be equally exceptional. This is particularly the case given the statutory requirement to exclude from consideration Mr Moussa's mental impairment. This is because an accused's mental impairment at the time of committing an offence might otherwise have been the principal reason for concluding that it would have been 'clearly unjust 8 Chokolich [60]. 9 Chokolich [61] - [62]. 10 Chokolich [66]. 11 Chokolich [72]. 12 Chokolich [78] - [81]. -- 11 of 13 -- [2026] WASC 355 PALMER J Page 12 given the circumstances of the offence and the person' to have imposed a sentence of life imprisonment;13 and (g) where the court's 'best estimate' of the sentence that the sentencing court would have imposed is life imprisonment, s 50 of the CLMI Act does not permit, or require, the court to determine the minimum non-parole period that would have been set if the person had been sentenced to life imprisonment.14 45 Where the court sets the limiting term with respect to a custody order made in relation to multiple charges, the limiting term should reflect the best estimate of the total effective sentence that the court would have imposed if it were sentencing the person for the offences.15 46 Mr Moussa conceded that the appropriate limiting term is life. In my view, that concession was properly made. 47 I consider that if Mr Moussa had pleaded guilty to the charge of murder, and the court sentencing him did not take into account his mental impairment, he would have received a sentence of life imprisonment. 48 Mr Moussa's assault on his father was unprovoked, brutal and sustained. His father's last moments would have been terrifying. His father would have been unable to comprehend the reason for his son's actions. 49 If Mr Moussa was criminally responsible for his actions, the seriousness of the offending would require a term of life imprisonment. The relevant mitigating factors: the assumed early guilty plea, Mr Moussa's prior good character and his cooperation with the police, would have little effect on the appropriate sentence given the seriousness of his offending. I am satisfied that there would have been no basis to conclude that it would have been 'clearly unjust given the circumstances of the offence and the person' to impose a term of life imprisonment. 50 In reaching this conclusion, I have taken into consideration the Pre-disposition Report dated 30 June 2026 that has been prepared. 13 Chokolich [81]. 14 Chokolich [89]. 15 Smith [37] - [41]. -- 12 of 13 -- [2026] WASC 355 PALMER J Page 13 51 I have also taken into account the victim impact statements prepared by Mr Moussa's sister, Ms Angy Iskander, and his brother, Mr Hany Moussa. Those statements speak about the character of their father, the sacrifices that he made for his family and how much he was loved and is missed. They also speak about their forgiveness for Mr David Moussa. What has happened is a tragedy for the entire Moussa family. 52 Ultimately, I am satisfied that the best estimate of the term of imprisonment that the court would, in all the circumstances, have imposed based on the assumptions outlined in s 50 of the CLMI Act is a term of life imprisonment. I set the limiting term of Mr David Moussa's custody order as the duration of his life. That limiting term is to commence on the date Mr Moussa was taken into custody, being 4 February 2025. Conclusion 53 For all of these reasons, I concluded that a custody order should be made and set the limiting term of Mr Moussa's custody order as the duration of his life. I certify that the preceding paragraph(s) comprise the reasons for decision of the Supreme Court of Western Australia. SK Associate to the Hon. Justice Palmer 25 AUGUST 2026 -- 13 of 13 --