A South Australian man who shot dead his son and his son's girlfriend, has failed in a bid to have his jail sentence for his "brutal, execution-style crimes" reduced.
In a judgment from the Court of Appeal on Thursday, Pawel Klosowski was told his 34-year non-parole period would stand, meaning the 47-year-old will be 80 before being eligible for release.
He had argued the sentence was manifestly excessive and did not take into account mitigating factors including his grief and contrition.
But in its unanimous decision, greeted with applause by the families of the two victims, the three appeal judges ruled that his sentence was within the permitted range and that Klosowski had not pointed to any errors in the sentencing process.
In their joint reasons, Justices Trish Kelly and Justice Mark Livesey said Klosowski's "brutal, execution-style crimes" warranted a severe sentence.
"Not only was this a double murder, but it involved an extraordinary response to what many would consider a banal domestic disagreement," they said.
"The appellant's offending, affected by alcohol, can be seen to be characterised by determination, brutality and purpose."
But the judges were also critical of public commentary in relation to the case, some of which they described as regrettable.
"Ultimately, a judge must sentence according to law," they said.
"Whether the sentence accords with the views of commentators or the media is of much less importance than whether the sentence meets the standards set by the appeal courts, including the High Court.
"In difficult and tragic cases, as in this case, it is particularly important that commentary be well-informed."
Klosowski pleaded guilty to the murders of his son Lukasz Klosowski and Chelsea Ireland, both aged 19, at his rural southeast property in August last year.
In sentencing, Justice Anne Brampton detailed how the argument had escalated with the killer berating his son at one stage for crying like a "little baby".
Acting deliberately and with purpose, Klosowski had retrieved the keys to his gun safe and loaded a shotgun before putting extra rounds in his pocket.
Lukasz was shot first in a bedroom and Klosowski had then reloaded his gun before firing at the locked bathroom door where Ms Ireland had hidden and called triple zero.
A second shot had killed her with her body found in the bath.
Because of his early guilty pleas, Klosowski was entitled to up to a 40 per cent discount on his minimum jail term. But Justice Bampton said such a discount would affect public confidence in the administration of justice.
She imposed the mandatory head sentence of life in jail but set a non-parole period of 34 years after applying a 15 per cent discount.
At the time, Greg Ireland, father of Chelsea said Klosowski's sentencing "marked the end of one incredibly difficult chapter" in the lives of both families.
"We've all got life sentences, but we're thinking this will probably be a life sentence for him as well," he said.