Mushroom Murderer Erin Patterson Killed Her Relatives with Poisonous Beef Wellington

In the charming Australian town of Leongatha, mom-of-two Erin Patterson lured her in-laws over for lunch under the guise of wanting to discuss her purported cancer diagnosis. On the menu: beef Wellington laced with lethal death cap mushrooms.

On July 29, 2023, the 48-year-old gathered her estranged husband’s parents, Don and Gail Patterson, both 70, as well as Gail’s sister, Heather Wilkinson, 66, and Heather’s pastor husband, Ian Wilkinson, around her dining room table and sought their advice on how to break the news of her cancer—which authorities later determined was a lie—to her children.

Erin’s ex, Simon Patterson, declined the lunch invite, and their kids were also absent.

Between the discussions on Erin’s health, family members dined on mashed potatoes and green beans, in addition to beef Wellington, a beef tenderloin dish made with with mushroom duxelles or paté de foie gras and wrapped in ham and puff pastry. For dessert, Gail brought an orange cake.

Following the discreetly toxic meal, Erin’s guests fell severely ill. Don, Gail, Heather and Ian were all admitted to the hospital with gastrointestinal issues within 24 hours, according to the BBC. However, Erin did not experience symptoms consistent with the others despite eating a seemingly identical meal. Erin’s refusal to admit herself to the hospital so staff could run tests left doctors perplexed and alarmed.

Within days, Don, Gail and Heather were pronounced dead at the hospital. They died from altered liver function and multiple organ failure, NPR reported. Ian spent several weeks in critical condition but recovered after receiving a liver transplant.

The deadly incident triggered a frantic police investigation. When authorities determined the victims had poisonous mushrooms in their systems, the evidence overwhelmingly indicated Erin intentionally sought to kill.

“What sets her case apart is that it involves a level of premeditation. Death cap mushrooms aren’t very common,” Dr. Vicky Nagy, senior lecturer in criminology at the University of Tasmania in Australia, tells A&E Crime + Investigation. “It's something that you actually have to put effort in to try and find.”

Victoria police arrested Erin on multiple charges of murder and attempted murder in November 2023. Despite pleading not guilty to the charges and insisting the deaths of her family members were a tragic accident, evidence presented during her trial in the Supreme Court of Victoria indicated the mass murder was carefully executed.

“This wasn't in the heat of the moment,” Nagy points out. “There were multiple victims at once, and there seemed to be a lot of planning that went into it.”

During the trial that commenced in April 2025 and ran for more than two months, the court was presented with several pieces of key evidence. Jurors learned Erin served the victims’ meals on gray plates, while she served herself on an orange platter, according to the BBC.

Furthermore, prosecutors alleged Erin’s cell phone pinged in areas where there were death cap mushroom sightings two months before the murders. She also conducted a death cap mushroom search on her home computer.

“She spent time in Facebook groups and other forums looking at true crime cases, looking at how people use death cap mushrooms to poison people,” Nagy explains. “All of this demonstrates a level of planning.”

Erin’s husband, Simon Patterson, testified that he suspected his wife previously tried to poison his food—such as pasta, chicken korma curry and a veggie wrap—several times in 2021 and 2022, prompting him to cancel on her the night before her lunch.

"I thought there'd be a risk that she'd poison me if I attended," Simon admitted to the court during a 2024 pre-trial hearing, Australia's ABC News reported. He said he thought he was her only target and believed his parents would be safe.

Prosecutors continued to present even more damning evidence: proof of a food dehydrator riddled with traces of death cap mushrooms that belonged to Erin. Surveillance footage captured her trying to get rid of it at a local dump.

“The evidence was strong. Disposal of the food dehydrator after the police had been to her house, and the fact that she left the hospital and didn’t want to get herself checked up when her in-laws were very unwell,” was suspicious, Nagy adds.

During cross-examination, Erin testified she thought her beef Wellington “was the perfect dish” for her in-laws, yet she maintained her innocence and stood by her claims it was an accidental poisoning, per The Guardian.

Still, the 12-person jury didn’t buy it, and they unanimously found Erin guilty on three counts of murder and one count of attempted murder.

“She proclaimed her innocence, and still does,” Nagy says. “She said that her behavior was the actions of someone who just didn't want to be blamed for what had happened.”

As for a motive, prosecutors did not offer one. “The only person who knows is Erin Patterson herself,” Nagy says.

In September, a judge handed down three life sentences for the murders of Don, Heather and Gail, plus another 25 years for the attempted murder of Ian, to be served concurrently. She is being held at the Dame Phyllis Frost Centre in Melbourne. Erin will be eligible for parole in 33 years, when she is 82.

On November 3, 2025, Erin's attorneys filed to appeal her conviction. Her legal team had to convince the the Court of Appeal that there may have been legal errors in Erin's trial because in Australia, appeals are not an automatic right. The grounds of her appeal had not been revealed at the time of its filing.