In a judgment on Wednesday, the High Court allowed an appeal by Peter Rex Dansie against a ruling by the SA Court of Criminal Appeal.
In that decision, the appeal court found against Dansie's argument that the original guilty verdict, delivered by a judge alone, could not be supported on the evidence at his trial.
Dismissing Dansie's action in 2020, Justices Mark Livesey and Greg Parker ruled it was open to the trial judge to find the murder charge proved beyond reasonable doubt.
In a dissenting view, Justice Kevin Nicholson would have quashed Dansie's conviction on the basis that it "would be dangerous in all the circumstances to allow the verdict of guilty of murder to stand".
In its decision, the High Court said Justices Livesey and Parker had misapplied a key test in relation to finding the conviction was reasonable.
It said for the appeal court to be satisfied that the guilty verdict could be supported required more than "mere satisfaction" that there had been no errors in each finding of fact by the trial judge.
"It required more than mere satisfaction as to the existence of a pathway to proof of guilt beyond reasonable doubt," the High Court ruled.
It said each member of the appeal court needed to ask whether they were independently satisfied, on an assessment of all of the evidence, that the only rational inference was that Dansie deliberately pushed the wheelchair into the pond, intending to drown his wife.
"The appeal is, therefore, to be allowed. The order of the Court of Criminal Appeal is to be set aside. The matter is to be remitted for rehearing," the High Court ruled.
Helen Dansie, 67, drowned after her wheelchair fell into a pond in Adelaide's parklands on Easter Sunday, 2017.
After his conviction, Dansie was jailed for life with a non-parole period of 25 years.
In his sentencing remarks, Justice David Lovell said the then 71-year-old was driven by selfish motive.
"Yours was an evil and despicable act," the judge said.
"Helen, your loving and devoted wife for over 40 years, had simply become a burden to you.
"This was a chilling, planned murder of a person whose mistake was to trust you."
25°C