An acquittal on a murder charge on the basis of a defence of self-defence is rare and, as with every criminal prosecution, much depends on the factual scenario of an individual case.
Self-defence can be either a full defence to a murder charge, leading to acquittal, or a partial defence that, if accepted, results in a verdict of manslaughter.
When an accused raises a defence of self-defence, the onus is on the prosecution to disprove that on the criminal standard of beyond reasonable doubt.
If a jury finds the prosecution has proven that an accused knew the force they used in response to an unlawful attack was disproportionate to the attack, and that a reasonable person would also consider the force excessive, that is murder.
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If a jury finds the prosecution has failed to prove that an accused did not honestly believe that the force they used was necessary for self-defence, but has proven that a reasonable person would consider the force used was disproportionate, that is manslaughter.
An acquittal arises when a jury finds the prosecution has failed to prove that an accused did not honestly believe the force they used in response to an unlawful attack was necessary for self-defence and has also failed to prove that a reasonable person would not have reached the same conclusion.
[ Delivery cyclist found not guilty on all counts in Josh Dunne murder trialOpens in new window ]
[ George Bento: Josh Dunne’s death ‘something I’ll regret for the rest of my life’Opens in new window ]
There is no definition in law of reasonable force and that is a matter left for determination by juries based on the facts and evidence in individual cases.
The facts of the incident resulting in the death of 16-year-old Josh Dunne were particularly complex. The evidence of the accused, 36-year-old Brazilian delivery cyclist George Bento, was that he and his friend, Guillherme Quieroz, had followed a bike thief through Dublin but when they tried to retrieve the stolen bike, they were set upon by a gang of men and youths.
Experienced criminal barristers said, in cases of complex facts such as this one, much depends on the momentum of the evidence at trial
Bento said he feared for his life and that of his friend and used a utility knife he had for cutting fruit to defend them from serious injury or death. He said he believed his actions saved his life and that of his friend.
His lawyers argued that when Bento first produced the knife he was reacting to a perceived threat from the man on the moped and that he and his friend did not attack the man even though, at that point, they outnumbered him two to one. The jury was told Bento and Quieroz had decided to leave but were prevented from doing so when the youths arrived and attacked them.
The prosecution accepted that Bento and Quieroz were acting lawfully in retrieving the stolen bike and were subjected to an unlawful attack by others. But it argued that when Bento first produced the knife to the man on the moped he was not acting in self-defence but was “acting the hard man”.
It argued the force Bento used after Josh Dunne and two other youths arrived was not reasonable or necessary and neither he nor his friend was being beaten when Bento took out the knife a second time. Dunne and the other youths were using only their fists and were unarmed, it said.
In his charge to the jury concerning the law, trial judge Mr Justice Paul Burns said if it was reasonably possible that Bento acted in defence of himself or another and used no more force than was necessary, he should be found not guilty.
Bento was ultimately acquitted of the charge of murder, two charges of assault causing harm and producing a knife in a manner likely to intimidate others.
Experienced criminal barristers said, in cases of complex facts such as this one, much depends on the momentum of the evidence at trial.
One said, given how the evidence ran during Bento’s trial, there was “little surprise” among the criminal bar at his acquittal. The factual scenario was very complex, some scenarios are more likely to attract sympathy than others and the “vulnerability of delivery cyclists” may have been a factor, he added.