Moral culpability
54As sentencing judge I must assess the moral culpability of the offender, which is a separate matter from the objective seriousness of the offence: McLaren v R [2012] NSWCCA 284 at [29] per McCallum J, McClellan CJ at CL and Bellew J agreeing. This requires a consideration not only of the facts relating to the commission of the offence, but also those that shed light on why it was committed. Although the offender accepted that he had not established that he was not fully aware of the consequences of his actions because of a disability, he submitted that his moral culpability for the murder was reduced because of his mild intellectual disability; polysubstance dependence; chronic psychotic illness, namely delusional disorder; and undiagnosed antisocial personality disorder.
55Dr Hepner, a clinical neuropsychologist who assessed him at the request of Legal Aid, opined that the offender's long-standing history of problems with anger, aggression and temper control can be explained by a combination of his limited intellect, his psychiatric condition and self-reported heavy drug use.
56The offender suffers from a mild intellectual impairment. The use of the term "mild" is apt to connote something of little consequence. But this is not the case when applied to intellectual impairment. As the High Court has said in Muldrock at [50] a diagnosis of mild intellectual impairment means that he is mentally retarded. The offender has an IQ of about 65. Mr Taylor, the neuropsychologist who first assessed him as having an intellectual disability in 1999, said:
"Mr Dunn's functioning was at a concrete and immature level, he was lacking in insight concerning the extent of his disability and he was impulsive, distractible and had a low frustration tolerance."
57Dr Chew, a forensic psychiatrist, treated the offender in a prison clinic from 1 June 2011 until 15 August 2012. Such sessions were often brief. He interviewed him on 19 February 2013, for the purposes of preparing a report for this hearing. He also gave oral evidence at the sentence hearing. He explained that those with an intellectual disability such as the offender's have low tolerance and difficulties in articulating their frustration with events or with others. They tend to respond physically, including violently, rather than verbally, because of their diminished repertoire of means of expression and their tendency to be impulsive.
58The offender submitted that at the time of the murder he was suffering from a delusion that the deceased was his ex-wife and that she had killed his two children. Each of these matters was delusional. He had never met the deceased before. I am satisfied by the evidence of Robyn Clark, solicitor, given by affidavit sworn 20 March 2013 that the offender does not have an ex-wife and has not fathered two children within the relevant period as alleged.
59In order to establish that his delusion played a part in the murder the offender relied on:
(i) a statement from Shane Bennett who was an inmate at Kempsey Correctional Centre between 21 August 2009 and January 2010;
(ii) a history that he had given to Justice Health two days after the murder;
(iii) instructions he gave to his solicitor, Robyn Clark, on 1 November 2010; and
(iv) a history given some time later to Dr Chew, a forensic psychiatrist, whom he saw for the first time on 1 June 2011.
60Mr Bennett recalled the offender being incarcerated at the Kempsey Correctional Centre some time between 21 August 2009 and the end of January 2010. He remembered the offender telling the other inmates that his wife had killed their two children. The expression of this delusional belief predated the murder by at least seven months.
61The offender gave the following history to Justice Health in the course of a mental assessment on 11 September 2010, two days after the murder:
"States alleged victim was his ex-wife
Married to her at age 16
Son was 2
Daughter was 4 months/ died in Wollongong hospital
States "she threw them out of the window" on my birthday."
62Ms Clark, whose evidence was not challenged, said that on 1 November 2010, at her first conference with the offender, he told her, referring to the deceased:
"She killed two of my kids. That's why I did it. I was engaged to her when I was 16 and I had two kids with her- Jessica born 1999 and Josh born 1997. I know her as Michelle. Both died at the same time- thrown out of the bedroom window. I was in Juvenile custody. My uncle had introduced us. She was about 10 years older than me. I had no contact with Michelle after the death of the children. I thought she was locked up."
63The offender told Dr Chew that he thought the deceased was his ex-wife. When Dr Chew asked the offender why he had not disclosed that in the ERISP, he explained that he thought that it would show that the murder was pre-meditated and that he would get a longer sentence. Dr Chew considered that the offender's belief that the deceased was his ex-wife was supported by the offender's history that he realised her identity when he saw a tattoo when they were having intercourse and that this was why he could not continue to have intercourse with her. As referred to above, I do not accept that the deceased and the offender had intercourse at all.
64The offender told police that he had never seen the deceased before. I consider that this admission represented his true mental state at the time of the murder. Although in the course of the ERISP the deceased mentioned his children and that they were dead, he did so most tellingly in the following context:
A 352 Then when she mentioned my kids, that's when I lost it.
Q 353 Why? Why did that make you lose it?
A Both of my kids are dead, and a woman killed them. My ex wife.
Q 354 How long ago was that?
A Five or six years ago. Nah actually, I rephrase that, 11 years ago. It happened in '99.
Q 355 How did Crystal know about your kids?
A Nah 'cause we were talkin' about them.
Q 356 Did you tell her what happened to them?
A Nah.
Q 357 So it's the case that she wouldn't have known that they were dead?
A Don't think so, don't think I told her.
[Emphasis added.]
65In the ERISP, the offender emphasised the word "woman" which I have highlighted above in italics. Gender is the only apparent link between the deceased and the ex-wife. Dr Martin, a forensic psychiatrist, whose report was relied on by the Crown also viewed the ERISP and noted that the offender did not link the deceased with his ex-wife, except in the context of the passage set out above. Although Dr Chew had access to the transcript and a partial DVD of the ERISP the portion he was able to view did not include the passage set out above.
66Notwithstanding Dr Chew's opinion and evidence and Dr Furst's opinion, I am not satisfied to the requisite standard that the offender was acting under a delusion at the time of the murder that the deceased was his ex-wife who had killed their two children. Accordingly, I am not satisfied that there was a causal link between the murder and the offender's delusions.
67The death of the deceased was brought about by the offender's low tolerance to frustration which was further reduced by the drugs he had taken. My impression after having viewed the ERISP, and taking into account the other evidence, accords with Dr Martin's, who reported:
"My summary of my impression from watching the interview is that he gives an account of having picked up a prostitute, that he had not met her before, that a row ensued in the context of trying to obtain drugs and him having an axe which he might have used in a robbery, and that he had been using amphetamines prior to the alleged offending. He gives an account of deliberately hitting her with the axe and then trying to dispose of the evidence to avoid arrest."
68Although I do not accept that, at the time the offender killed the deceased, he believed that she was his ex-wife who had killed their two children, I accept that he came to adopt that delusion as a way of explaining, if not justifying, even if only to himself, what he had done. That he had earlier been under the delusion that he had been married with children and that his ex-wife had killed his two children is an indication of his disordered thinking as well as his potential danger to the community on release.
69Dr Chew opined that the offender's prognosis with respect to delusional disorder is guarded. The diagnosis of mild intellectual disability, for which there is no specific treatment, is permanent.
70I accept that the offender's diminished capacity to reason and respond appropriately, by reason of his intellectual impairment and his anti-social personality traits, lessens his moral culpability for the murder. However, his capacity to control his impulsive responses was further compromised by his drug-taking in the hours prior to the murder. He had some appreciation that taking ice had the effect of making him "snap". Although he initially said that he did not know why he snapped he later admitted that it was because of the drugs he had been taking and that he had just "lost the plot".
71The offender, when he was asked by police what he was thinking at the time when he was hitting her:
"I was just thinking, you nagging bitch fuckin' shut up, shut up, just let me think."
72That his criminal record as an adult indicates an offence of violence in 2007 but no other violent offences until the murder of the deceased is a further indication that the drug-taking was a significant cause of his violence towards the deceased, against the background of his already compromised mental state.
73Although the offender did not submit that his prospects of rehabilitation were good, he contended that there was some prospect that he could be rehabilitated by control of his drug intake, anger management courses and other instruction designed to moderate his responses and increase his tolerance. He submitted that his ability to overcome the delusion that the deceased was his ex-wife was evidence of his capacity to be rehabilitated.
74He is currently taking Quetiapine, an anti-psychotic drug, for his delusional disorder which is focussed around his fixed belief that his ex-partner killed his two children many years ago. His current dose is less than the maximum.
75I accept that there is some prospect that the offender's mental state will improve, at least in the controlled environment of custody. Already, his abstinence from illicit, non-prescribed drugs has improved his mental state, as has the anti-psychotic drug which he has been taking.
76The offender has requested that I make a recommendation about treatment while he is in custody. The expert evidence establishes that he is likely to benefit from such intervention, including anger management courses and treatment for drug and alcohol abuse, both while he is in custody and following his release. Accordingly I make the recommendation that the offender be provided with services that address his intellectual disability, his delusional disorder and his poly-substance abuse.
77The Crown accepts, and I am satisfied that, the offender feels a degree of remorse within the limits of his mental state.