SAFM star Mark ‘Soda’ Soderstrom’s relative Yvonne Fletcher revealed as the infamous Poison Ivy Killer

A popular Adelaide media personality has revealed he is related to an infamous murderer nicknamed the Poison Ivy Killer.

Mark ‘Soda’ Soderstrom revealed on SAFM his great aunt was sentenced to death for the murder of her two husbands

A popular Adelaide media personality has revealed he is related to an infamous murderer nicknamed the Poison Ivy Killer.

Mark ‘Soda’ Soderstrom told The Advertiser his great aunt Yvonne Fletcher, who was sentenced to death in 1952 for the murder of her two husbands.

Fletcher was the first Australian to be convicted of murder by thallium poisoning, more commonly known as rat poison, with her sentence eventually downgraded to life in prison.

Soderstrom said Fletcher’s first husband, his grandmother’s brother Desmond George Butler, suffered a painful sickness, experiencing nerve, organ and brain damage for nine months before passing away in 1948.

Yvonne Fletcher was charged and convicted over the thalidomide poisoning deaths of her two husbands – Desmond George Butler in 1948 and Bertram Fletcher in 1952.

Yvonne Fletcher was the great aunt of Adelaide media personality Mark ‘Soda’ Soderstrom. Picture: Matt Loxton

Five years later, Fletcher’s second husband Bertram Fletcher became suspicious of his wife and reported her to the police, accusing her of poisoning his morning toast and lunch Thermos.

“My uncle was poisoned with rat poison and then the woman poisoned another guy,” he said.

“They sort of both lost their minds and I think they might have become disabled and couldn’t walk and all these different things,”

Soderstrom said Bertram Fletcher experienced similar symptoms to Butler in 1952, raising alarm bells with neighbours and the police.

“The police started to put two and two together because there were a number of similarities,” he said.

The exhumation of Fletcher’s dead husbands revealed thallium to be the culprit for both deaths.

Fletcher was arrested in May, 1952 and sentenced to death in September at the Central Criminal Court.

The judge, Justice Kinsella, acknowledged that Yvonne suffered domestic abuse at the hands of her second husband, but said there was no mistreatment by the first husband despite accounts of Desmond’s excessive drinking habits.

Fletcher eventually evaded the death penalty as in 1955 NSW abolished the practice and her sentence was changed to a lifetime of imprisonment.

Soderstrom said the family links to Fletcher appeared to be a “weird secret” among his relatives.

“No one ever really talked about it … I don’t know if it’s because there was an embarrassment or sadness,” he said.

“When my mother told me about it, I was fascinated.”

Fletcher’s trial was highly publicised in the media and inspired a wave of copycat poisoners, with thallium almost untraceable.

However, when Soderstrom raised his secret with his radio colleagues this week, they didn’t believe him initially.

“They started googling it and went ‘Oh my god, you’re telling the truth,’” he said.

He said he was comforted by the fact Fletcher was married into the family and not a blood relation.

“I don’t know if she was an absolute nutcase or she just married two pretty ordinary blokes,” he said.

“But because I’m connected to Desmond by blood, I’m going to run with absolute nutcase.”

The poison Fletcher used is tasteless, odourless and colourless and in the late 1940s to early 50s, it was readily available at all supermarkets, pharmacies and hardware stores to curtail NSW’s rodent infestation.

Between 1952 to 1953 there were 10 deaths in NSW due to thallium poisoning and 36 hospital admissions.

Fletcher was released from Long Bay Jail in 1964 after serving almost a decade behind bars.

Soderstrom’s mother, Betty Soderstrom, said she was only two or three when her uncle died, and the circumstances surrounding his death were rarely discussed.

“In those days you didn’t really discuss those kind of things,” she said.

“I never really talked to mum about it.”

Ms Soderstrom said she still keeps in touch with her cousins and they discuss their uncle’s death.

“We were all too young to know him,” she said. “It’s fascinating.”