A court has heard that a Sydney woman who stabbed her 18-year-old sister to death would take it back if she could.
Kathleen Worrall, 22, was charged with murdering her sister Susan in their Strathfield home in October 2008.
The prosecution accepted her guilty plea to the lesser charge of manslaughter due to mental illness.
During sentencing submissions, her mother Maureen has broken down in the Supreme Court while speaking of her daughter’s sorrow and remorse.
She said her daughter would “take it all back in a moment” if she could.
The court heard that when Kathleen Worrall killed her sister she had a hormonal condition – congenital adrenal hyperplasia – but had stopped taking medication for it.
A forensic psychiatrist said suddenly stopping the medication could produce very high levels of testosterone.
The court heard the sisters argued about access to the internet.
It heard Kathleen Worrall attacked her younger sister one week after an argument about a hair straightener.
The court heard that Worrall had brought knives and had researched stabbings on the internet.
Worrall sat in the dock looking across at her family and shaking her head, at times crying.
Justice Elizabeth Fullerton noted that, although she had an underlying mood disorder, the degree to which her mind was impaired at the time of the attack needs to be considered in sentencing.
The judge said Worrall had written her a letter talking about the unqualified love she had for her sister and how close they were.
But Justice Fullerton pointed out that some of the contents of the letter were in conflict with what Worrall had told a doctor about her relationship with her sister.
She said Worrall told a psychiatrist her sister was “Miss Cute and Popular” but people who knew her knew it was not true.
The judge said the 22-year-old told the doctor that her sister Susan was callous, had threatened her and that they did not get along.
Documents tendered show that Susan Worrall had 50 stab wounds. Her older sister was found with three knives.
Kathleen Worrall is expected to be sentenced in June.