When Professor Derek Abbott first proposed that she was the missing link to solving the infamous Somerton Man mystery, Rachel Egan was dubious.

After a decade of detective work, the professor had written to her suggesting she shared the DNA of the dead man on Adelaide's Somerton beach, whose case has baffled professional and amateur sleuths around the world since 1948.

When they first met at a fancy restaurant in Brisbane, Ms Egan thought the professor was a "nerd" who showed an unusual interest in her ears and teeth.

"He wanted to look at my ears and my teeth. He was also after my DNA," Ms Egan says. "It's probably the first request I've had from a man to do that."

But the intrigue quickly went from the professional to the personal. Before the sun set the next day, they had decided to marry.

"People have said that possibly Derek married me for my DNA," Ms Egan laughs. "And I think there is some truth to that."

They are now happily married with three children, yet the spectre of a man who has been dead for 70 years hovers over the couple.

Exhumation approved, but who pays?

He was found resting against the sea wall at Adelaide's suburban Somerton Beach. He looked peaceful: passers-by thought he was sleeping.

Except, the quality of his clothes — the highly polished new shoes, the neatness of his grooming — indicated he was not the kind of man who would be sleeping outside.

The weeks leading up to Christmas are a time when families come together. But after his body was found at 6:40am on December 1, 1948, no-one would come to claim him. No-one ever has.

Who he was, how he died, where he came from, where he was going: these questions have never been answered. His fame has grown exponentially as every passing decade has failed to uncover his secrets, the public interest intense. Now, for the first time, the answers are within reach.

South Australian Attorney-General Vickie Chapman, who studied the case at law school, has granted conditional approval for an exhumation, with the proviso that taxpayers don't foot the bill. It is expected to cost about $20,000. That money has yet to be raised.

Professor Derek Abbott is the man pushing for the exhumation.

"It is frustrating that so much time has passed and an exhumation hasn't happened yet but I think the time is now right for that. The technology is there and I think the will is there," he says.

Professor Abbott wants Somerton Man's DNA. He suspects Somerton Man fathered a child and left a generational legacy and that Rachel Egan is the Somerton Man's granddaughter.

Professor Abbott, who specialises in electrical engineering at Adelaide University, first discovered the case when he read about it in a magazine while he was at the laundromat. It was a story of such intrigue.

"I thought it would be a great project for my students," he says.

The Somerton Man brought together his possible granddaughter and the professor: a love story. Was it his own love story that brought him to Adelaide 70 years earlier?

No ID, no wallet, no name

The erasure of the identity of the Somerton Man was meticulous, either by design, theft or foul play.

The labels had been cut off his clothes — both the garments he was wearing and those in the neatly packed suitcase he had left at the train station that was found six weeks later.

He had a cigarette tucked behind his ear and one partially smoked between his cheek and his coat collar.

There was no wallet, money or identification on his body or in his suitcase.

An autopsy found he was a fit 40 to 45-year-old man, an athlete "in top physical condition".

Pathologist John Cleland noted his toes had a slight wedge and his calf muscles were high and pronounced. He speculated he could be a ballet dancer or a long-distance runner. His teeth were unusual.

His lateral incisors were missing, his sharp canines had grown in next to his front teeth. But his dental records were not able to be matched with any known person. International circulation of his fingerprints yielded no positive identification.

At an inquest in July 1949, the coroner found he had not died of natural causes. His stomach and kidneys were deeply congested with blood, his spleen was three times the normal size.

It was the opinion of the doctor who carried out the post-mortem examination that death had been caused by heart failure due to poisoning.

But tests failed to reveal any foreign substance in the body.

The body was embalmed and a death mask was made of his face.

Speculation the Somerton Man was a spy now shifted to include suicide and murder.

Several months later, a tiny rolled-up piece of paper was found hidden deep in the fob pocket of his trousers. It was printed, not handwritten, and said Tamam Shud.

A newspaper reporter claimed it came from a 12th-century Persian poetry book that was fashionable at the time, The Rubaiyat, written by Omar Khayyam.

It meant "the end" or "the finish". The poem is about living life to the fullest and having no regrets when it ends.

Police advertised in a local paper, asking if anyone had a book with the words Tamam Shud ripped out.

A local chemist handed in a book that had been thrown in the back of his car around the time the body had been discovered.

A page had been written on and torn out. It was the indentations of this writing that have provided the most baffling clues.

Along with sequences of encrypted letters that have never been deciphered, was a phone number that led police to a 27-year-old nursing student who asked that her name not be made public.

When they took the woman to see the death mask, she nearly fainted. In spite of her obvious distress, she denied she knew him. Police allowed her name to be withheld because she was a potential witness.

For the rest of her life, she refused to cooperate with police.

By the time Professor Abbott uncovered her name — Jessica Ellen "Jo" Thomson — it was too late to ask her. She had died in 2007, taking her secrets with her.

"The fact that she kept everything secret and turned this whole case into a mystery is part of the equation too," Professor Abbott says.

"Because if she had just fessed up in the '40s and there was no mystery, I wouldn't be here today and we wouldn't be married."

Although Jo would go on to marry car dealer George Thomson once his divorce was finalised, she had a son who was about 16 months old when the Somerton Man died 400 metres from her house.

Towards the end of her life, she told a friend she would always be grateful to George for marrying her when she was pregnant with her first child, even though he wasn't the father.

Through his research, Professor Abbott concluded that Somerton Man and Jo Thomson were known to each other.

He believes they had a child called Robin.

"Perhaps he did come to see Jo Thomson and his son and died for whatever reason there out on the beach, and perhaps it was in her interest to deidentify him," he says.

"She was in a relationship with another man who would go on to be her husband, and she just didn't want this ghost from the past coming back to mess up her current existence."

Could Somerton Man have a son?

In 2009, Professor Abbott consulted with dental experts who concluded the Somerton Man had the rare genetic disorder of hypodontia, affecting his lateral incisor teeth, present in only 2 per cent of the population

University of Adelaide professor of anatomy Maciej Henneberg examined images of the Somerton Man's ears and found his cymba (upper ear hollow) was larger than the lower, a feature possessed by only 1 to 2 per cent of the population.

A photo of Robin showed he shared both these anomalies. The chance of coincidence is estimated at between one in 10,000 and one in 20,000.

"Therefore it is likely that the Somerton Man and the person suggested to be his son are actually related," Professor Henneberg says.

"I believe there was a fairly elaborate attempt to confuse investigators."

Source: ABC