'I need to kill you': Dad to daughter, 10

On the day he killed her mum and sister, a 10-year-old Melbourne girl wrote in her diary that she was worried about her dad.

"I think he's really anxious right now. I'm really scared," the youngster shared.

That evening in January 2022, in the toy room of their family home, she saw her father stab her mother.

He was in a drug-induced psychosis, triggered by his use of ice. The 40-year-old later revealed he believed he had reacted in anger when she tried to stop him harming himself.

His bloodied wife ran from the house screaming for help, followed by her terrified 10-year-old daughter who feared for her six-year-old sister.

While her mother tried to flag down a passing car and ran to a neighbour's porch for help, the older girl ran around to their front door.

She was headed into the street when her father came down the driveway, chasing after her.

"I need to kill you," he shouted, pursuing her at increasing speed.

He tripped on the driveway and gave her a vital few seconds to escape. The girl, now 11, ran to a neighbour's home where she spoke to emergency services.

"My mum is bleeding really, really bad ... I don't know if she's alive or not," she said.

"My little sister, she's six-years-old, and I'm really worried about her."

The terrifying violence toward his wife continued on the neighbour's front porch, where she was begging them to let her inside.

Her husband of 13 years stabbed her eight times in all over an attack lasting nearly 10 minutes. He shouted "I love you" among other, largely incomprehensible, remarks.

The 39-year-old woman was declared dead at the scene. Her six-year-old daughter died in hospital the next day.

While the 10-year-old escaped physical injury there's no doubt she experienced significant trauma, a Victorian Supreme Court justice said on Thursday.

The man has pleaded guilty to two charges of murder.

Prosecutors said the man's wife had called police earlier in the day, concerned he was stressed, anxious and drug-affected.

They attended and found the man "pleasant and polite", noting while he appeared to have taken drugs he was not a risk to himself or others.

He had no prior history of family violence against his wife or children. But court records show he had convictions for assaulting a woman he had an affair with in 2014.

The woman's parents described her as bubbly, bright, and eager to share even the smallest achievements of her daughters.

They had already grieved the losses of two children before her death and described losing their daughter and a treasured granddaughter - the sunshine of their lives - as bringing life to a standstill.

The father, who cannot be identified in order to protect the surviving child, apologised in a letter to the court.

He said it was unbelievable to him that he destroyed his family, asking forgiveness from his wife's parents, his parents and surviving daughter.

"I have done wrong to you and your mum and sister. Please forgive me," he wrote.

"Your dad is still a good man and loves you loads. Be always a good girl, the way you always were."

His lawyer said the man believed, because of drug-induced psychosis, that his family had been kidnapped and were in danger.

The man had been hospitalised in April 2021 after displaying increasingly erratic behaviour in the context of methamphetamine use.

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