THE JURY in the Martin murder trial must consider if Michael Phillip Martin was acting under "extreme provocation" if they conclude he killed his father, a court has heard.
Supreme Court Justice Peter Hamill raised the issue of provocation in his summary to the jury on Wednesday.
The summation is expected to continue tomorrow morning after which the jury will retire to deliberate.
Justice Hamill said extreme provocation could be found if the conduct of the deceased involved a serious indictable offence toward the accused and caused the accused to "lose self-control".
It would also need to reasonably cause an "ordinary person" to lose control to the point of inflicting grievous bodily harm on the deceased.
Extreme provocation could be considered even if it conduct occurred years before the act which killed them.
This was relevant to the jury's deliberations, Justice Hamill said, due to evidence about Michael Martin's abusive upbringing with his father.
As defence barrister Gabriel Wendler has previously told the jury: "His father treated him like rubbish, he exposed him episodically to crimes including murder, drug dealing, and association with motorcycle gangs."
Only if the jury decides that Martin did in fact kill his father can extreme provocation become a partial defence for Martin's actions.
The issue has not been raised until now because it was not part of the defence case, in which Martin Jnr argued he was the victim of a home invasion alongside his father on the night of April 13, when his father died of stab wounds.
The jury was told it had three options available when deliberating the murder charge against Martin - guilty, not guilty, or guilty to the lesser charge of manslaughter.
The latter verdict might be reached if the jury decides Martin was involved in the killing but under extreme provocation.
Martin has pleaded not guilty to murder and denies he was ever involved in his father's death.
Alongside murder the jury must also deliberate the two charges against Martin arising from the earlier home invasion of April 7.
Over that occasion, Martin is charged with causing grievous bodily with attempt to murder his father and causing grievous bodily harm with intent to Edmund Manning.
Justice Hamill said the jury needed to consider whether the Crown had proved if the accused was involved at all in the events of that night.
To be guilty, the accused must have been present at the scene.
He could not be guilty "unless he was there playing a part in the violence", Justice Hamill said.
The trial continues.