A researcher in the case of the Somerton Man says he has solved the decades-old mystery, identifying the figure as a Melbourne-born electrical engineer.

Adelaide University researcher Derek Abbott believes the unknown man found slumped and lifeless at Adelaide's Somerton Beach on December 1, 1948, was Carl "Charles" Webb, a 43-year-old engineer and instrument maker.

The case has long baffled detectives and amateur sleuths, and is regarded as one of Australia's most enduring mysteries because of strange clues linked to it, including a suspected code and a book of Persian poems.

While the mystery man's remains were exhumed last year by SA Police, Professor Abbott has in the meantime persisted with his own independent efforts to crack the case.

He said after using hairs from a plaster bust of the man to gather DNA evidence, researchers in Australia and America had further narrowed the search "to build out a family tree containing over 4,000 people".

Working in conjunction with US investigator Colleen Fitzpatrick, Professor Abbott said that, in March this year, suspicions fell on Webb, who was born in 1905 but later identified "as a person with no death record".

Professor Abbott, who last week spoke to the ABC about his work, added "the final pieces of DNA proof came into place" on Saturday, "triangulating to Charles Webb".

Professor Abbott said that Webb was born in Footscray on November 16 in 1905 to Richard August Webb (1866 - 1939) and Eliza Amelia Morris Grace (1871 - 1946).

He said their investigations had also found a link to the name "T. Keane" which was printed on the Somerton Man's tie.

"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.

"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."

Professor Abbott also said there was a potential explanation as to why the Melbourne resident was in Adelaide.

"We can't say for sure, but we can speculate.

"We have evidence that he had separated from his wife, and that she had moved to South Australia, so possibly, he had come to track her down."

Relatives alive

Professor Abbott said the team had used popular genealogical DNA databases, like Ancestry.com, to find Mr Webb'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."

He said he had tracked down and spoken to Mr Webb'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."

He added that there was sufficient DNA evidence to "definitively" disprove any links with his wife Rachel Egan, whose father — ballet dancer Robin Thomson — was believed to have potentially been a descendant of the Somerton Man.

"The fact he (Thomson) has a rare dental and ear condition matching the Somerton Man appears to be an extraordinary coincidence."

Search continues

Professor Abbott said after more than a decade on the case, the discovery felt like summitting a mountain.

"It kind of feels like climbing Mount Everest, and having that mixture of elation that you're at the top, but also tiredness and exhaustion," he said.

However, he said his work was not over.

"Now there's the historical work of actually digging further and finding out about the man's life and his circumstances and what might have exactly led to this particular situation.

"So there's still work to do."

SA Police have been contacted for comment.