An Adelaide man found guilty of murdering a teenage girl 45 years ago suffered a significant miscarriage of justice because scientific evidence at his trial was seriously flawed, the High Court has heard.
Frits Van Beelen was originally sentenced to death but served 17 years' jail for murdering 15-year-old Deborah Leach, who was found buried in seaweed at Taperoo Beach in July 1971.
The Full Bench of the South Australian Supreme Court rejected his latest appeal in July last year, ruling against his contention that new and compelling evidence had emerged.
But the High Court agreed to consider an appeal against that ruling and heard on Wednesday that later science had seriously discredited evidence relating to the time of death given at the trial by forensic scientist Colin Manock.
Defence counsel Kevin Borick QC told the court that Dr Manock's evidence was so wrong it should never have been presented to the jury as a key factor in the case.
"It had no basis at all in science," defence counsel Kevin Borick told the court.
"It had no scientific validity. Dr Manock was completely wrong."
As a result, Mr Borick said there had been a substantial miscarriage of justice.
Van Beelen has always maintained his innocence and his latest bid to overturn his conviction relies on relatively new legislation in South Australia which allows for a fresh appeal if new evidence emerges.
The legislation was successfully used in 2014 to overturn the conviction of Henry Keogh who was jailed for the murder of his fiance Anna-Jane Cheney after also being convicted largely on flawed evidence from Dr Manock.
Mr Keogh was in the High Court on Wednesday to watch Van Beelen's appeal, as was Gordon Wood, who was wrongly convicted in 2008 of the murder of his girlfriend Caroline Byrne whose body was found at the bottom of The Gap in Watsons Bay in 1995.
Outside the court, Mr Wood said he was there to "support justice" and he believed there had been a miscarriage of justice in Van Beelen's case "because of Manock".
But in his response to the appeal, South Australian Director of Public Prosecutions Adam Kimber told the court that while Dr Manock was wrong in limiting the time of death to one hour, based on the stomach contents of the dead girl, a wider period did not necessarily exclude Van Beelen from having killed her.
He said Van Beelen admitted to being on Taperoo Beach for a period of time when Miss Leach was also on the beach.
Van Beelen was the first man in SA to be convicted of a crime largely on forensic evidence which also included the analysis of hairs and fibres found on the victim.
The High Court hearing will continue on Thursday.