‘Somerton Man’, as he is known, was found dead on Somerton Park Beach in Adelaide on the morning of December 1st 1948.
Professor Derek Abbott from the University of Adelaide who has been a researcher on the case since 2009 said just last week that he thought that the dead man could be Irish.
In a new twist in the case, Abbott has said that the case has been solved, with the man has been identified as Carl ‘Charles’ Webb, a 43-year-old engineer and instrument maker from Melbourne, Australia.
The enduring mystery has captured the attention of detectives and internet sleuths and left them baffled.
Abbott originally worked on the theory that the man was Irish because many of his belongings were inscribed with the name ‘Keane’.
"It turns out that Carl Webb has a brother-in-law called Thomas Kean, who lived just 20 minutes drive away from him in Victoria,” he told ABC Australia.
“So it's not it's not out of the question that these items of clothing he had with T. Keane on them were just hand-me-downs from his brother-in-law."
The man’s body was exhumed last May and taken to a forensic lab in the hope of obtaining DNA to carry out testing to identify him.
Working with American investigator Colleen Fitzpatrick, the team used popular genealogical DNA databases, like Ancestry.com, to find the man’s distant relatives.
"The first cousin we found was on his paternal side and the second one we found was on the maternal side," he said.
"So, it's a triangulation from two different, totally distant parts of the tree, so that's very convincing."
Professor Abbott has also tracked down and spoken to the man’s living relatives.
"I have spoken to them, except they're all of a generation well below him and so none of them knew him and have no photos in their old family albums or in their garden sheds, unfortunately.”
"I'm hoping, as his name gets out there, there will be somebody that will have an old photo album in a garden shed somewhere."
The South Australian police force has yet to confirm that the case has been solved.
The man’s cause of death could not be determined, with authorities branding it an “unparalleled mystery”.
He was found lying on his back with his head resting against the sea wall and it is believed the man died while asleep.
Somerton Man was dressed in a suit, and there were no obvious signs of injury.
A search of his pockets found various items including cigarettes, matches, a comb and an unused second-class rail ticket from Adelaide to Henley Beach.
Six weeks later, staff at the Adelaide railway station discovered a brown suitcase that was checked into the station cloakroom on 30 November 1948, just one day before the man’s death.
It was confirmed to be his and in the case, authorities found the clothing marked with the name ‘Keane’.
Months after his death, a small rolled-up piece of paper with the words ‘Tamám Shud’ was found in a pocket sewn into his trousers. The text, which means “ended” or “finished” in Persian is included on the final page of Rubaiyat of Omar Khayyam.
After a public appeal, the exact book from which the phrase was torn was found.
The book had been found not far from the location of the man’s body in an unlocked car parked nearby.
In the back of the book, a coded message was found, fuelling a theory that the man was a spy.
While cryptographers said that they could not provide "a satisfactory answer" to what the code meant, they added that if the text were an encrypted message it had "insufficient symbols" from which a clear meaning couldn’t be established.
The case has been compared to that of Peter Bergmann, an unidentified man who was found dead on a beach in Sligo in 2009.
Despite extensive investigations, the man who went under the pseudonym has never been identified.