Now we might finally have answers, and, sorry espionage fans, they’re much more pedestrian than originally thought.
Using hair from the Somerton Man, Derek used DNA evidence to narrow down the man’s relations to roughly 4,000 people.
To help comb through this enormous family tree, Derek engaged a US investigator who helped him find Charles Webb, a man born in 1905 but identified “as a person with no death record". What made Charles a particularly solid lead was his link to someone with the initials “T Keane”, his brother-in-law, Thomas Keane.
Charles also had a good reason to be in Adelaide.
"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,” Derek told the ABC.
But what about the mysterious Persian phrase? Well, according to Derek, Charles was a fan of poetry, often writing his own. “Taman Shud” comes from a 12th century poetry book called Rubaiyat of Omar Khayyám.
There’s still work to do. Derek would like to research Charles’ life further and track down any living relatives who might have more information about the man.
"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.
"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.”
South Australian Police are yet to verify Derek’s finding.
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