Shortly after midnight, he made a 111 call at the Sturges Rd train station admitting he attacked her.
At 4.29am on February 8, he was told by Detective Lee Bigelow that he was being charged with murder.
READ MORE:
• Martin Marinovich trial: The 111 call made by the accused
• Martin Marinovich trial: Police officer describes alleged murder scene
Today in court, Bigelow read from his notebook what the defendant had said.
"I don't know what to say. It's all like a bad dream," he said.
"We had an argument. I can't even tell you what it was about.
"I remember having my hands around her neck, then it is a blur.
"I must have grabbed the blanket and then the hammer from the bookshelf."
During cross-examination by defence lawyer Shane Tait, Bigelow described the defendant's demeanour.
"He was calm, I would describe him as reflective. He was tired.
"I think he was considering what had taken place and how it would affect his life from here."
When questioned further about his reaction to the charge, Bigelow added: "No, not overly emotional. I don't think he was surprised."
Earlier today, the victim's friend of nearly 40 years, Janet Daniel, told the court Martin Marinovich was agitated when she saw him at his mother's hospital bedside on February 4.
"He was twitching, twitching. And he jumped from one foot to the other."
She had never seen him like that before and he told Daniel he could no longer cope.
"And I said to him: 'Don't take her home. Leave her at the hospital'," she said.
Daniel told the court Martin Marinovich was ordinarily gentle and non-violent.
"They got along very well. They had a few words sometimes, everybody does."
She said he had been looking after his mother "since he was 9 years old."
The past few years had been really hard for him because she had become incontinent and would often collapse in the house.
"Martin would have to physically pick her up off the floor," Daniel said.
"She couldn't stand to do the cooking.
"He never went out much at all because she couldn't be left."
Martin Marinovich was often up throughout the night to help his mother, she said.
"He didn't get any sleep."
When she had last visited their Oratia home before Christmas 2018 she was surprised by how grubby it was.
It had once been kept spotless, the court heard.
"That was her pride and joy, that little house," Daniel said.
Earlier in court, detective Anna Fager described the state of that same small home when examined by police following Noeleen Marinovich's death.
Fager, the officer in charge of the scene, said surfaces were covered in a layer of dust of up to 5mm and cobwebs hung on the light fixtures.
She said the victim's bedroom was cluttered, with clothes piled on top of clothes in a mix of dirty, clean, old and new – some still had tags on.
In the kitchen, cereal boxes were on the chairs, grease was splattered behind the stove and mould was around the window frames.
Several cards in the dining room marked special occasions like mother's day and birthdays.
"Both from Martin to his mum and vice versa," Fager said.
The trial, which is scheduled for two weeks, continues tomorrow.