A five-year-old girl saw her father stand over her mother as he brandished a knife the night he has been accused of stabbing his wife to death inside the family's Gordon home, her aunt told a court.
The trial for Maged Mohommed Ahmed Al-Harazi heard his daughter and son, then aged seven, told relatives they saw blood on their father's shirt and his son had seen him wash a knife the night of their mother's death in March 2015.
Their aunt also gave evidence the boy told her in the months after Sabah Al-Mdwali's death that his father instructed him to tell police their grandfather killed his mother.
Mr Al-Harazi, 36, was charged with murder after the body of his wife, 28, was found on a bed inside their Knoke Avenue house in the early hours of March 17.
He pleaded not guilty, and has maintained Ms Al-Mdwali's father and brother murdered her that night.
They were arrested soon after her death, but later released without charge.
Prosecutors say the couple's three children - then aged seven, five and 10 months - were home at time of the killing. The Crown case is that Mr Al-Harazi stabbed his wife 57 times as she breastfed their infant son after a heated argument.
The trial has heard ongoing tensions in the couple's marriage stemmed from Mr Al-Harazi's wish to return home to Yemen, a desire not shared by his wife.
Ms Al-Mdwali's siblings gave dramatic evidence in the ACT Supreme Court as Mr Al-Harazi's trial entered its third week on Monday.
The court heard the couple's young daughter and son had spoken to one of Ms Al-Mdwali's sisters about the night their mother died in May of that year.
She said the couple's daughter said she saw her father standing on the bed on top of her mother as he held a knife.
The witness raised her right hand in a fist above her head as she demonstrated the action her niece had shown her.
When she asked the girl if she'd been able to see her mother, her niece said: "I saw my mum's legs."
The girl told her aunt she went back to her room and woke her older brother.
The court was told both children said they saw their father come out of the room with blood on his shirt.
The boy told her during the conversation he had also watched his father wash a knife.
He said Mr Al-Harazi then put the children in the car and drove to a location where he threw a rubbish bag, the court heard, before they later went to the police station.
"[The boy] told us that his father told him to say that my father and [brother] killed Sabah," his aunt said.
Under cross-examination from defence barrister Ken Archer, Ms Al-Mdwali's sister admitted her family had been told by police and psychologists not to ask the boy and girl about what happened that night but the children "felt like talking".
"They have to talk, they needed to talk. They've seen their father killing their mother," she yelled.
Mr Archer: "Did this conversation happen at all?"
The witness: "Yes, it happened."
Earlier, another sister said she and Ms Al-Mdwali, who did not speak English, had gone to court with divorce papers because she wanted to split with Mr Al-Harazi soon before she died.
"In the last argument they had, she'd had enough of him," her sister said.
"She didn't want to be with him."
The application was rejected because the couple had only been separated for several weeks.
On one occasion, Ms Al-Mdwali's sister muttered under her breath to Mr Al-Harazi as she walked past on her way out of the court.
She later admitted, under cross-examination, she had called him a "cockroach".
The trial continues.