Issues at the trial and findings
34The jury were instructed as to the elements of the crime of murder and manslaughter. Three matters should be noted about the instructions to the jury.
35First, the instructions to the jury did not refer to provocation and reflected the fact that no question of self defence or other lawful justification for Mr Bryce inflicting harm upon Ms Barton arose in the trial. At all stages Mr Bryce denied assaulting Ms Barton. It follows that the jury's verdict reflects a finding that Mr Bryce committed manslaughter by an unlawful and dangerous act. In this context, dangerous means that a reasonable person in the position of Mr Bryce would have realised that, by his act, Ms Barton was exposed to an appreciable risk of serious injury.
36Second, the jury were specifically instructed that, unless they were satisfied beyond reasonable doubt that Ms Barton died as a result of an injury inflicted at or after 5:00pm on 15 May 2012 (i.e. after her return to the unit), then Mr Bryce had to be acquitted of murder and manslaughter.
37This direction reflected the manner in which the Crown ultimately put its case. A significant part of the trial was concerned with whether the subdural haematoma must have been inflicted after Ms Barton returned to Mr Bryce's unit. To that end, there was competing medical evidence as to the likely progression of the symptoms of her subdural haematoma. The Crown pointed to the various observations of Ms Barton's lucidity that were made throughout 15 May 2012 as negating the suggestion that she was already fatally injured by the time she returned to the unit at around 5:00pm. The defence pointed to uncertainties in that evidence, as well as to the tendency evidence I have noted above, as raising a reasonable possibility that Ms Barton could have sustained her fatal injuries prior to her return to the unit.
38It follows from their verdict that the jury were satisfied beyond reasonable doubt that Ms Barton died as a result of an injury occasioned after her return to the unit on 15 May 2012.
39Third, the jury were instructed that, although it was necessary for the Crown to prove beyond reasonable doubt that it was the voluntary act or acts of Mr Bryce that inflicted the injury that caused Ms Barton's death, the Crown did not have to identify the precise act that caused her death (R v PL [2009] NSWCCA 256; 199 A Crim R 199 at [46] to [49] per Spigelman CJ).
40In this case there was no direct evidence as to precisely how Ms Barton suffered a subdural haematoma. The post mortem had only revealed internal bruising that might have been associated with the infliction of the subdural haematoma. There were no obvious signs of a scuffle and struggle in the unit. There was no witness who described overhearing a violent confrontation. The post mortem examiner, Dr Johan Duflou, accepted that the type of force that could cause a concussion type injury could have inflicted the subdural haematoma suffered by Ms Barton. Dr Duflou accepted that "as a minimum, a fall to the ground [could] do it and a punch, as an example [could] do it". Dr Parkinson's evidence was to similar effect, although he stated that "usually a subdural haematoma would require a reasonably significant force to cause it". He agreed that a "fall against the wall or something like that" could have caused it.
41The end result is that, other than the facts necessarily found by the jury, there is much uncertainty associated with ascertaining the basis upon which Mr Bryce is to be sentenced. In R v Olbrich [1999] HCA 54; 199 CLR 270 ("Olbrich") at [27] Gleeson CJ, Gaudron, Hayne and Callinan JJ confirmed that a sentencing judge may not take into account facts adverse to an offender unless they are established beyond reasonable doubt, and may take into account facts favourable to an offender if they are proved on the balance of probabilities.
42In this case Mr Bryce is to be sentenced on the basis that some time after 5:00pm on 15 May 2012 he engaged in some voluntary act that inflicted a subdural haematoma upon Ms Barton which caused her death. The nature of his act was such that it was both unlawful and of a kind that a reasonable person in his position would have realised that by that act Ms Barton was exposed to an appreciable risk of serious injury. Beyond this, and consistent with Olbrich, I cannot make any finding as to the nature of the act. Further, I do not find that at the time he committed the act Mr Bryce realised that his act was dangerous in the requisite sense.
43Three further factual matters should be noted at this point. First the Crown submitted that Mr Bryce's failure to seek medical assistance for Ms Barton, and his attempt to deflect the police from assisting her when they arrived at the unit on the evening of 15 May 2012, were aggravating circumstances of the offence.
44I have already referred to the evidence of Mr Parlak and Mr Stokes as to Ms Barton's condition when they observed her in the corridor that evening. It is clear that by this time she was suffering from her subdural haematoma. Understandably Mr Stokes and Mr Parlak thought she was affected by drugs and alcohol. However, I am satisfied beyond reasonable doubt that Mr Bryce knew at that time that she was affected by her head injury. The evidence of other witnesses in the trial who observed her in the afternoon did not suggest that she was visibly affected by drugs and alcohol. A blood test taken from Ms Barton after her admission revealed the presence of methadone and cannabis. A pharmacologist, Dr Judith Perl, testified that Ms Barton's level of impairment during the afternoon of 15 May 2012 due to cannabis was "not likely to have been high, if at all".
45In these circumstances I am also satisfied beyond reasonable doubt that Mr Bryce knew that Ms Barton needed medical attention. He knew her to be outspoken and tough and that only a reasonably serious injury would have had that effect on her. I am, however, not satisfied beyond reasonable doubt that he knew or believed her injuries to be life threatening. I accept that Mr Bryce cared for Ms Barton. He would not have left her to die.
46In Dulihanty v R [2013] NSWCCA 275 at [68] Johnson J (with whom Hoeben CJ at CL and Latham J agreed) held that the immediate departure of the offender in that case from the premises where the "clearly injured victim [was] alone with no apparent means of assistance, [could] properly be regarded as a circumstance of aggravation of the offence". Those observations apply here.
47Second, the Crown urged the Court to find that the motive for Mr Bryce's actions was Ms Barton telling him that she had obtained an AVO (as revealed in his ERISP). I am not satisfied beyond reasonable doubt of that matter. While, in the ERISP Mr Bryce referred to Ms Barton making comments to that effect while they were having sex, there is nothing in the ERISP or any other part of the evidence that points to a connection between the imparting of that information and Mr Bryce attacking Ms Barton.
48Third, for the sake of completeness I am also not satisfied beyond reasonable doubt that Mr Bryce assaulted Ms Barton on the morning of 15 May 2012. Ms Barton claimed that she was assaulted with a toilet brush, yet none was found. Ms Barton also claimed that she was on the telephone to her father when the attack occurred, yet that was clearly not the case.