Distinctive physical features strongly suggest that the Somerton Man had a son with the mysterious Jestyn, but she had no intention of keeping her former lover in her life. Instead, she led Prosper Thomson, her married car-salesman boyfriend, to believe that the boy was his. Whether the Somerton Man threatened to reveal himself as the real father or out Jestyn as a Soviet Spy, she had ample motive to poison him. But did she?
Unsolved Murders: True Crime Stories show hosts Carter Roy and Wenndy Mackenzie track the life of Jestyn and follow the movements of a masked man to try to answer this question.
The Somerton Man accuses Jestyn of being a spy for the Soviet Union. She doesn’t deny it outright, but she argues that agreeing with a few Communist ideas and being able to speak Russian doesn’t mean she is a spy. Yet the trust between them is shattered, and he leaves without seeing their son Robin. On his way out the door, the Somerton Man vows to have the boy taken away from her.
Long before meeting the Somerton Man or Alfred Boxall, Jestyn trains to be a nurse at a hospital in Sydney, Australia. Real name Jessie Harkness, Jestyn sometimes ventures out for drinks after work. During these outings, she separately meets the Somerton Man and Alfred Boxall. She gives each a copy of The Rubaiyat of Omar Khayyam.
Pregnant, morning sickness forces Jestyn to quit nursing school. Her married boyfriend Prosper Thomson believes the child is his. He jokes about the funny shape of Robin’s ears, commenting that they didn’t come from his family. Jestyn steers the conversation away to Prosper’s wife. He promises to divorce her and marry Jestyn after. It’s a promise he eventually keeps.
To keep the extramarital affair a secret, Jestyn does not give the police her real name when they ask her about the body found on Somerton Beach, and they do not pry. She lies about not knowing the Somerton Man. Years later, her second child, Kate Thomson, claims her mother was a Soviet spy.
The scene flashes back to two Australian codebreakers trying to puzzle out the code in the Somerton Man’s copy of the Rubaiyat. Neither have seen anything like it and are frustrated by its seemingly uncrackable nature. In looking at various copies and editions of the Rubaiyat, investigators learn that the formatting of the Somerton Man’s copy is unique.
Unsolved Murders: True Crime Stories show host Carter Roy thinks the Somerton Man’s Rubaiyat is a one-time pad, a code mathematically unbreakable without the encryption key, which is used only once and then destroyed.
This isn’t the first time authorities have seen a mysterious edition of the Rubaiyat. Just four years before the Somerton Man’s death, a man named Joseph Saul Haim Marshall was found sitting on a bench overlooking the water at a park in Sydney with a copy of the Rubaiyat laying across his chest. He had just committed suicide by drinking poison. While the copy was labeled as a seventh edition published by Methuen in London, upon being asked, the publisher said they only printed five editions.
In later years, micro-writing is found in the Somerton Man’s code, as well as Jestyn’s signature in the copy she gave Alfred Boxall. Carter considers the possibility that Jestyn poisoned the Somerton Man to keep him silent about his discovery that she was a double agent. Wenndy, on the other hand, finds it hard to believe that she would kill the father of her first child. The show hosts debate Robin Thomson’s parentage.
Carter points out that the child’s distinctive ears and lack of lateral incisors match the Somerton Man’s features and notes that both are rare genetically inherited traits, making it highly unlikely that Prosper Thomson, or any other man, fathered Robin. Carter proposes another possible motive for murder and one that has nothing to do with espionage. Jestyn may have killed the Somerton Man to keep him from telling Prosper the truth about Robin’s parentage.
The episode cuts back to a scene between Jestyn and the Somerton Man, where she’s trying to cut the latter out of the family picture. Adamant about staying in his son’s life, the Somerton Man threatens to tell Prosper that he’s the boy’s real father. Jestyn makes an innuendo about her ability to make him disappear.
Flash-forward to the time period shortly after the Somerton Man’s death. A masked man stalks the wife of Keith Mangnoson, one of the many people to try to identify the Somerton Man’s body. Keith initially thought the unknown man was Carl Thompsen, someone he previously worked with. Although he wasn’t Carl, Keith becomes upset upon seeing the body of the Somerton Man. On June 21st 1949, a battered white car tries to run over Keith’s wife, Roma Mangnoson, while she walks down the street. The masked man inside threatens to hurt her if she doesn’t stay away from the police.
Around the same time, J. M. Gower, secretary of the Largs North Progress Association, and A. H. Curtis, the mayor of Port Adelaide, receive threats from an anonymous caller to stay away from the Mangnoson case.
But what is “The Mangnoson Case”? The case revolved around the death of Keith and Roma’s two-year-old son Clive. Prone to bouts of fugue due to mental illness, Keith disappeared with the boy and accidentally poisoned him with his grandmother’s epilepsy medication. The masked man likely hounded the Mangnoson family for that incident, rather than their fleeting involvement identifying the Somerton Man. As for Keith’s strong reaction to seeing the unknown man’s body, it was likely a result of his untreated PTSD.
In the end, both Carter and Wenndy agree that Jestyn probably murdered the Somerton Man. They only disagree on the motive. But what do you think? Did Jestyn poison him because he found out she was spying for the Soviet Union? Or did she kill him to keep him silent about Robin’s true paternity?