David Tran is facing trial in Sydney for the murder of his former lover, Daiane Pelegrini, 33, in 2020.
The victim's ex-partner, Marcelo Antunes De Ataide, told the Supreme Court through a translator Ms Pelegrini always left the back door of her western Sydney home open.
"Because she believed that Australia was safe," he said on Tuesday.
Tran allegedly became desperate to reignite the relationship after it had disintegrated, and flew into a jealous rage after breaking into her Oatlands home and discovering her with her new boyfriend, Steven Qaqos.
He is accused of fatally stabbing Ms Pelegrini to death on August 3, assaulting Mr Qaqos with a knife and unlawfully entering her home intending to stalk or intimidate.
Ms Pelegrini originally met Mr De Ataide in Brazil in 2007, and the pair later had a child and moved to Australia in 2016 as she aspired to become an aged care nurse.
Their relationship began to fray in after February 2020, although the pair continued to spend time together and remained intimate in the days up to her death.
Texts exchanged between the victim and Tran show them arguing over whether or not she was his "girlfriend", and Tran making unannounced visits to her home, crown prosecutor Rossi Kotsis previously told the court.
On one occasion he arrived unannounced at a holiday the mother took at Bundeena, south of Sydney.
The court was also played a body worn camera video of a walk through of the crime scene, which showed the blood-soaked Oatlands home after the alleged attack.
Puddles of blood were seen on the living-room carpet where paramedics had attempted to save Ms Pelegrini before she died at the scene.Â
Mr Tran's lawyer Nicole Carroll said the defence would not dispute many of the facts put forward by the prosecution, but would argue her client was mentally ill when he killed Ms Pelegrini.
Lifeline 13 11 14
beyondblue 1300 22 4636
