The drowning murder of George Duncan is regarded as an unsolved crime and remembered as a tragedy, but it has also been described as a "watershed" moment in the story of gay law reform in Australia.
Today marks 50 years since the 41-year-old University of Adelaide gay law lecturer was thrown into the River Torrens by a group of men.
The incident occurred on the night of May 10, 1972, and London-born Dr Duncan — who had been in Adelaide for barely six weeks, and could not swim — drowned in the murky water.
"When his body was ultimately recovered and dragged from the Torrens with arms awry, it was unceremoniously thrown back into the river when television cameras arrived late, demanding graphic film to screen in the nightly news," former High Court judge Michael Kirby later reflected, in a speech to the Adelaide Law School.
Though never proven, suspicions were quickly raised about police involvement in the incident, and two vice squad members were tried and eventually acquitted of Dr Duncan's manslaughter.
At the time, homosexuality was illegal in every Australian state, but reform was on the way, in no small part due to the death of Dr Duncan.
Don Dunstan's government became the first in Australia to decriminalise male homosexuality.
"There was a movement amongst the community, amongst parliament, to actually update our laws, and South Australia became the first jurisdiction in Australia to actually decriminalise homosexuality for consenting adults," Adelaide City councillor Keiran Snape said.
The Duncan anniversary coincides with a moment of renewed focus on gay-hate crimes in Australia, in light of the recent conviction in Sydney for the 1988 murder of mathematician Scott Johnson.
While there are many differences between the two cases, there are also striking similarities: Like Dr Duncan, Scott Johnson had been born overseas before moving to Australia to pursue academic interests.
"There's definitely a lot of parallels. There is an inference … that the Scott Johnson case was based around sexuality, and we know in all certainty that the murder of Dr George Duncan was based around his sexuality," Mr Snape said.
"These things have happened throughout our recent history. The conviction in the Scott Johnson case goes to show the passage of time doesn't hide all, doesn't cover all, so perhaps we can hope for justice in the future."
'We actually got extraordinary change'
To mark the half-century anniversary, Adelaide will today host a memorial event at the university footbridge near where Dr Duncan died, as well as the official unveiling of a freshly repainted Pride Walk in Light Square.
Also known as the Rainbow Walk, the multi-coloured path highlights steps along the road to legislative change and social inclusion, such as the instigation of the now-annual Pride March and the 2017 legalisation of same-sex marriage.
"Back in October, there was actually some homophobic graffiti, a bit of an attack made on the walk, with 'repent' spray-painted on rather largely," Mr Snape said.
"While we did get it cleaned up pretty fast … it was brought to my attention that the Rainbow Walk itself was in a state of disrepair."
The Duncan story has been told and re-told — most recently in the operatic oratorio Watershed: The Death of Dr Duncan, which was one of the centrepieces of the Adelaide Festival.
Adelaide-based author Tim Reeves this year published a book on the case — which he has investigated for several decades — but is resigned to the fact that the crime may never be solved.
"With each passing day, that likelihood becomes smaller and smaller," the author said.
While not entirely giving up hope, Reeves said that, in the meantime, it was important to reflect upon the "senseless and awful" event, but also the changes it led to.
"I just hope people will take a moment today [to] remember that 50 years ago there occurred a shocking killing in this state … and to remember Dr Duncan," he said.
"Out of a very sad and traumatic event we actually got extraordinary change."
