Man cleared of 1983 'ulcer murder'

A 30-year-old murder conviction has been overturned by Western Australia's Court of Appeal on the back of Nobel Prize-winning ulcer research by Perth-based scientist Barry Marshall.

Chris von Deutschburg was a teenager in 1983 when convicted of murdering Stavros Kakulas in a scuffle during a burglary at the 86-year-old man's home in Perth's seaside suburb of Scarborough.

Mr von Deutschburg, then 19, received a life sentence on the basis Mr Kakulas died of a bleeding duodenal ulcer seven days after the crime.

The ulcer was said to have been brought on by the stress of the home invasion.

Professor Marshall and his colleague Robin Warren won Nobel Prizes in 2005 for proving bacteria, rather than stress, caused stomach ulcers.

Prof Marshall told AAP he had been involved in the case from the beginning, when he had already conceived his award-winning theory, but was yet to prove it.

"There were just a couple of people on our side and everyone else just believed this traditional theory," he said.

In proving his theory, Prof Marshall acted as a human guinea pig, downing a bacterial brew that made him very ill, but gave new hope of treatment for millions of sufferers.

Once the research gained worldwide attention, Mr von Deutschburg, who spent seven years in prison before being paroled in 1990, looked to Prof Marshall's work as a way to clear him of his murder conviction.

The scientist got behind him, writing to the State Solicitor's Office saying Mr von Deutschburg could not be guilty, prompting former state attorney-general Christian Porter to refer the case to WA's Court of Appeal.

Yesterday, Justices Carmel McLure, Robert Mazza and Michael Buss announced their unanimous decision, saying the basis of the conviction had been overtaken by the groundbreaking discovery by Prof Marshall and Mr Warren.

The judges said Mr Kakulas's duodenal ulcer was likely to have existed before the home invasion in June 1983.

Evidence provided by Prof Marshall, and also by PathWest Laboratory Medicine chief forensic pathologist Clive Cooke, raised enough doubt in the judges' minds to make them conclude Mr von Deutschburg should not have been convicted of murder.

"If the jury had heard Professor Marshall's and Dr Cooke's evidence, in addition to the evidence adduced at trial, it must be necessarily have entertained a doubt about the appellant's guilt," the judgment read.

"A miscarriage of justice occurred at the trial."

In his petition on behalf of Mr von Deutschburg, Prof Marshall said there was no likelihood that Mr Kakulas's injuries either worsened or contributed to the duodenal ulcer.

On Friday, Prof Marshall said the case was one for the law books.

"This is really a landmark case ... a milestone if you like," he said.

It was important for Mr von Deutschburg to clear his name, he said.

"To have a conviction at a young age ... that affects your career and your job prospects for the rest of your life.

"These things are very important and maybe you can't just be a bit irresponsible in your youth in case something does happen like that.

"It affects you for a long time."