Defence Suggests Father May Have Administered Insulin to Himself in Murder Trial

The defence lawyer for a woman accused of murdering her parents by injecting them with insulin has told a jury there is a "reasonable possibility" her 94-year-old father administered the drug to himself.

Raelene Polymiadis, 65, of Craigmore, is standing trial in South Australia's Supreme Court after pleading not guilty to the separate murders of her parents, Brenda and Lynton Anderson.

The pair were both 94 years old when they died 14 months apart, in 2022 and 2023.

Prosecutor Michael Foundas previously told the jury it was alleged Ms Polymiadis, their youngest daughter and type 1 diabetic, injected both her parents with "fatal doses of insulin".

"She poisoned them to death, she murdered them," he said.

The court heard neither Mr or Mrs Anderson were diabetic.

Defence counsel for Ms Polymiadis, Marie Shaw KC, told the jury today they would need to consider several "key issues" when arriving at a verdict.

Mrs Shaw said the jury would need to "exclude as a reasonable possibility" that Mrs Anderson's decision to "enter the end-of-life care phase" was because she had pre-existing medical conditions, and not because of issues allegedly caused by the administration of insulin.

She also said the accuracy of Mrs Anderson's blood tests, which identified insulin, would be questioned.

Mrs Shaw said when considering the death of Mr Anderson 14 months later, the jury would need to consider whether the prosecution's case had excluded "the reasonable possibility that Mr Lynton Anderson administered the insulin to himself".

"He had not only talked about suicide but had stated to a … support worker that he knew how he would do it, that will be an issue for you."

Mrs Shaw also told the jury if the prosecution proved the "substantial cause" of Mrs and Mr Anderson's deaths was the administration of insulin, the jury would also need to be convinced it was Ms Polymiadis who administered it.

She said Ms Polymiadis denied administering the drug to either of her parents.

Ms Polymiadis's brother Graham Anderson also gave evidence in the trial on Wednesday.

Mr Anderson said that, after the death of their mother, their siblings had discussed the presence of insulin in her system.

"All the options were on the table, so my belief was it could be human error or something.

"I'll be honest, I didn't know."

The trial is expected to continue for three months.