A spontaneous verbal argument between a couple at a Port Fairy caravan park led to the fatal stabbing of a man in 2019, a court has heard.
Jessica Wilson, 36, is standing trial in the Warrnambool Supreme Court over the alleged murder of Marcus Adams in the early hours of September 20, 2019.
In opening addresses on Thursday, the jury was told they must consider whether Ms Wilson intended to kill or cause "really serious injury" to the victim, or was acting in self-defence.
Senior crown prosecutor Nanette Rogers said the accused and the deceased were in a relationship since late 2018 and were residing at the caravan park together in mid-2019.
She said the jury would hear evidence of the accused woman being involved in a serious vehicle collision on August 24 that year - about four weeks before the fatal stabbing.
She said Ms Wilson had remained in hospital for some time, with Mr Adams regularly travelling from Port Fairy to visit her as she slowly recovered.
Ms Rogers said the couple had returned to the caravan park on afternoon of September 19 and seemed "happy in each other's company".
But she said the jury would later hear evidence from a number of residents at the caravan park who overheard arguing later that evening.
She said one witness would tell the jury that she heard banging and yelling from the caravan next door, followed by the accused yelling something to the effect of "you drug f**** dog".
She said other witnesses would say they overheard the accused saying "get off me" and the victim asking to be left alone.
Ms Rogers said jurors would be told that Ms Wilson yelled "Help! Help! Help!".
She said it was not disputed that Ms Wilson caused a fatal stabbing injury to the deceased man while in the caravan.
She said the jury would hear from medical experts in relation to injuries, which included a 15-centimetre stab wound to the victim's back, as well as bruising and tenderness to Ms Wilson's neck.
Ms Rogers said the crown case was put in two ways - that the accused woman took possession of a knife and when the deceased approached her in an attempt to take the weapon, she stabbed him to the back and in doing so, intended to kill or cause really serious injury.
She said an alternative explanation was that a minor assault occurred by the deceased on the accused and that Ms Wilson "unnecessarily" defended herself.
Andrew Waters, representing Ms Wilson, told the jury his client acted in self-defence.
He said many things in the case were not in dispute, including the identity of Ms Wilson, but the jury should find the accused woman did not intend to cause death or serious injury.
Mr Waters said it was the defence case that the accused was threatened with a hammer and grabbed around the neck during an altercation with the victim, who she then stabbed to the back in self-defence.
The deceased's mother told the court her son started using marijuana when he was aged 16 or 17 and that she was aware of him later moving on to harder drugs, although she didn't know what kind.
Mrs Adams was asked about allegations of Ms Wilson being with another man at the time of the serious car accident.
She said she had heard about the allegations and that her son did not question Ms Wilson because he believed she was going through enough.
Mrs Adams said that following the accident, her son spent a lot of time travelling to and caring for Ms Wilson in hospital.
The witness said nothing seemed untoward about her son's relationship with Ms Wilson and she agreed that it was the closest he'd ever been to anyone in his life.
She agreed that her son was previously in a relationship with another woman who now had intervention orders in place against him.
The court heard from a number of witness who were residing at the Port Fairy caravan park on that fatal night.
One female witness, who was visibly upset during cross-examination, said she woke up and heard banging and crashing and a female who she assumed was Ms Wilson asking where her wallet was.
She said she only knew the victim on a "hi and bye" basis.
A second woman said she woke in the middle of the night to her dog barking and a male and female arguing.
She said she heard the female say "help me" about five or six times.
She said her partner told her about 3am that there was an ambulance at the park and a man on the ground.
A male resident of the park said he went to bed at 10pm and woke up to what sounded like two males arguing about 2.40am.
The trial continues on Friday and is expected to run until mid-December.
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