29 The scientific officers who attended the unit located many areas of blood staining throughout the living area and in the bedroom where the deceased's body was found. They also located the knife used to inflict the stab wounds and the damaged television set. This evidence, whilst serving to locate in general terms the site of the stabbing and the assault with the television, did not advance the Crown case at trial as to the order in which the injuries were inflicted or the precise mechanism and the degree of force that was used.
30 I am satisfied that the offender's account of the attack is unreliable and unacceptable since it is in large measure inconsistent with the forensic evidence. While I do not consider that he has deliberately set out to deceive police or minimise his responsibility for the deceased's death, the fact remains that the spread and severity of the injuries that were revealed on autopsy, and the spread and pattern of blood in the unit, were consistent with a brutal and unprovoked attack. I accept however that the objective gravity of the offence is diminished by the fact that there was no entrenched animosity between the two men and that the fatality is largely, if not wholly, due to the offender's state of intoxication and his diminished ability to control an outburst of aggression, as distinct from his conduct being the result of deliberation. The jury verdict is consistent with that view. The fact that within a very short time of arriving at the unit where the confrontation with the deceased erupted into violence, the offender was involved in another physical altercation with a man he was drinking with fortifies my conclusion that the offender was exhibiting recognised hallmarks of alcohol-fuelled aggression, likely to have been exacerbated by his having injected ice.
The expert evidence
31 Associate Professor Reid, who gave evidence at trial, is a professor of neuropsychology at the Prince of Wales Medical Research Unit. He performed a neuropsychological assessment of the offender. Importantly, he was provided with a PET scan of the offender's brain prepared by Dr Lowe, a neurologist, and interpreted by a specialist radiologist, Dr Choong. The scan confirmed organic brain damage. He was also provided with a copy of a report from Associate Professor Starmer, to whom I have already made reference, and the results of psychometric testing undertaken by Mr Diamond. Additionally, he was provided with reports from two psychiatrists, Dr Allnutt and Dr Westmore.
32 The purpose of the neuropsychological assessment was to examine the offender's cognitive function in order to determine whether he suffered from any impairment of the brain consistent with the neurologist's findings of brain damage. Associate Professor Reid came to the view that the offender was a man of average intellectual ability and that, despite the organic brain damage, there was no significant impairment of his intellectual functions. The specific deficits revealed on neuropsychological assessment were in the areas of memory and cognition. It was the professor's view that the abnormalities were permanent when the offender's current functioning was compared with his pre-morbid intellectual ability. While Associate Professor Reid was unable to find any objective evidence of poor impulse control, he noted that the offender's descent into serious drug and alcohol abuse from an early age was, from a behavioural perspective as distinct from the test data, at least partly explained by volitional defects.
33 Dr Lowe, a consultant neurologist, considered the results of the testing undertaken by Mr Diamond and Associate Professor Reid and regarded the test results as consistent with the abnormalities in the brain revealed on the PET scan. In Dr Lowe's view, the abnormalities were related to impulse control. He described this as the degree to which inhibition and disinhibition co-relate. He regarded the likely behavioural display reflected in the offender's conduct on the day of the killing as not uncommon in a person after 20 years of alcohol and drug abuse. He regarded the organic brain damage and the associated tendency to disinhibition as likely to be accentuated by the effects of alcohol and other drugs. He said:
"…if you have an underlying basis of that you just have to add alcohol and drugs on top of that and that would obviously trigger or accentuate any underlying change.."