An Adelaide grandfather was killed by his wife and her lover on the same day his fifth grandchild was born, a court has heard.
Steven Hinrichsen, 63, was found stabbed to death at his Morphett Vale home in December 2018.
Mr Hinrichsen's wife, 44-year-old Tanya Hinrichsen, and her lover, 47-year-old Gavin Scott Skinner, were found guilty of murdering the father of seven and grandfather of five because "he was in the way".
Their friend, 48-year-old Robert John Thrupp, was found guilty of the lesser charge of manslaughter.
During sentencing submissions today, the Supreme Court heard the murder was carried out with an "extreme level of violence" and that Mr Hinrichsen — who used a wheelchair — was struck at least 53 times.
Daughters tell of pain caused by murder
In a victim impact statement, Mr Hinrichsen's daughter Lisa told the court she was in labour when she found out her father — who was very excited to meet his new grandchild — had been murdered.
"My son and father now share the same day but for completely opposite reasons.
"My father was my hero — he always lifted me up and was always proud of me.
"He was proud of all his children and grandchildren; he loved us more than we ever knew."
Lisa Hinrichsen told the court she was also very close with his wife — her stepmother Tanya — who "took our dad and grandfather away".
"I will never understand why you didn't just leave — why you thought an affair and murder were the only options," she told the court.
"Dad was never perfect but he definitely didn't deserve what you have done to him."
The three teenage daughters of Mr Hinrichsen and Tanya Hinrichsen — who cannot be identified — told the court during a victim impact statement that they wanted nothing to do with their mother.
"I'm embarrassed to know my mum; I want you to know that I'm disappointed and ashamed of you," they said in a joint statement.
"I cannot believe someone can be so cruel."
Dispute over Tanya Hinrichsen's involvement
Prosecutor Carmen Matteo told the court Mr Hinrichsen was sedated at the time making him "incapable of defending himself in any way".
She said Skinner inflicted most — if not all — the fatal injuries but that blood patterns indicated there was more than one set of hands applied to Mr Hinrichsen during the assault.
She said Tanya Hinrichsen "intentionally encouraged the killing" and provided the keys to Mr Hinrichsen's house and "access to the vulnerable victim".
But Hinrichsen's lawyer, Grant Algie QC, told the court the "overwhelming evidence" was that she was asleep at the time of the murder and asked the court to grant "as much mercy as the legislation permits" in sentencing her.
The court heard she was appealing against her conviction.
He told the court there was no evidence to sustain the allegation his client had provided the keys to Mr Hinrichsen's house and that during past assaults, she had "calmed or defused the situation".
"If she'd actually been there, it wouldn't have happened," Mr Algie told the court.
But Ms Matteo told the court that "bold assertion" was not able to be reconciled with the jury's verdict.
"The killing of the deceased was talked about in text messages; it was talked about repeatedly; the talk escalated," Ms Matteo said.
"Her crime was a considered one.
"She desires that her husband would be killed."
No background of violence
The court heard the mother of six — who had never been employed — had no relevant criminal history and no "tendency revealed towards violence at all".
The court heard Skinner and Thrupp accepted the jury's verdict.
Thrupp's lawyer, Chris Weir, said his client had no history of violent offending, no animosity towards the victim and was a "very low risk" of violent offending in the future.
"It was never in my client's contemplation that what happened would happen," he told the court.
"He did not physically get involved or take part in what was effectively the killing of Hinrichsen.
"He wishes he could turn back time and that this did not happen to Mr Hinrichsen."
Hinrichsen, Skinner and Thrupp will be sentenced next week.
