Toby Loughnane is fighting a murder charge in the Supreme Court of Victoria, after instead admitting to Ms Hamka's negligent manslaughter - a charge prosecutors say does not go far enough.
His barrister Daniel Sala on Tuesday flagged he would argue Ms Hamka succumbed to a drug overdose rather than violence.
He urged a jury to consider the evidence dispassionately after it heard prosecution allegations he said probably stoked hatred towards Loughnane.
Prosecutor Kristie Churchill alleged Ms Hamka had been in a "relatively brief but violent and controlling relationship" with Loughnane before he murdered her at his Brighton home in April 2021.
In the months before Ms Hamka's death, Loughnane physically assaulted her and also sent messages threatening to injure and kill her, Ms Churchill said.Â
The messages included, "I'm going to split your skull", "I'll go to (jail) just to see you suffer you dog", "you're dead" and "wait until I get my hands on you dog", the prosecutor alleged.
Loughnane also pursued Ms Hamka in a car in 2021, followed her into her family home and threatened her friends, Ms Churchill said.
The last time her mother saw Ms Hamka was on April 9, 2021, when Loughnane was screaming at her to get in a car before she left with her alleged murderer, the prosecutor said.
Ms Hamka was spotted next day on CCTV at a Brunswick Woolworths before she was last seen alive in a "confronting" video filmed by Loughnane, wherein she was half-naked and he was mocking her, Ms Churchill said.
A friend of Loughnane's later saw Ms Hamka dead in the foetal position in the shower of his Brighton home, the prosecutor alleged.
Ms Churchill accused Loughnane of trying to cover up Ms Hamka's murder, alleging he sent her several messages after she died, sought a friend's help to buy a steam cleaner off Gumtree and disposed of her body in dense bushland.
Police found a significant number of cleaning products at Loughnane's home days after Ms Hamka's death.
Almost two years later - in May 2023 - they received information from Loughnane's lawyers about the location of Ms Hamka's body, the prosecutor said.
Officers later found Ms Hamka's bones in thick bushland at Cape Schanck on the Mornington Peninsula.
Mr Sala said the defence would focus on three key pieces of evidence, including the final video of Ms Hamka, the observations of Loughnane's friend and the fact both his client and Ms Hamka were extensive drug users.
The jury would hear evidence about the drug GHB, the barrister said.
"This is the world in which these two people occupied in April 2021," Mr Sala said.
"It can be quite disgusting. It brings out the absolute worst in people."
The world of drug use was critical to the case and Loughnane accepted responsibility for Ms Hamka's alleged fatal overdose, the barrister said.
"What you have not heard (from the prosecution) is anyone say, 'this is how she died'," Mr Sala said.
The trial continues on Wednesday.
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