An Australian mother, Erin Patterson, 50, has been found guilty of the triple murder of her estranged husband's parents and aunt, along with the attempted murder of a fourth guest, after serving them a deadly beef Wellington laced with poisonous death cap mushrooms. The verdict, returned by a jury in the Supreme Court of Victoria after a nine-week trial and six days of deliberation, has captivated Australia and drawn international attention, with the case often referred to as the "mushroom murders."

The fatal lunch took place on July 29, 2023, at Patterson's home in Leongatha. Her guests included her former parents-in-law, Don and Gail Patterson, both 70, and Gail Patterson's sister, Heather Wilkinson, 66. Heather's husband, Ian Wilkinson, a well-known pastor, was also present. All four fell gravely ill after consuming individual portions of beef Wellington, mashed potatoes, and green beans. Tragically, Mrs. Wilkinson and Mrs. Patterson died on August 4, 2023, followed by Mr. Patterson a day later, all succumbing to organ failure. Reverend Wilkinson spent seven weeks in hospital but survived the poisoning.

Prosecutors argued that Patterson knowingly laced the beef pastry dish with the highly toxic Amanita phalloides, commonly known as death cap mushrooms. During the meal, Patterson reportedly ate from a smaller, tan-colored plate, while her guests' portions were served on four large grey dinner plates, suggesting a deliberate act of poisoning. Her estranged husband, Simon Patterson, with whom she shares two children and had been separated from since 2015, was also invited to the lunch and initially accepted but ultimately declined, a crucial detail highlighted during the trial.

The prosecution's case dismantled Patterson's defense that the presence of the poisonous fungi was a terrible accident due to unknowingly foraged mushrooms. While it was not disputed that Patterson served the mushrooms or that they caused the deaths, the jury's unanimous guilty verdicts indicated they rejected her claims of accidental inclusion and found that she knew the lunch contained death caps and intended for her guests to die. Prosecutors did not offer a definitive motive for the killings but pointed to strained relations between Patterson and her estranged husband, as well as her past frustrations with his parents. The court also heard that Patterson had fabricated a cancer diagnosis as a ruse to explain inviting her guests that day, a claim she later acknowledged was a lie, made in panic.

Key evidence presented during the trial further undermined Patterson's credibility. It was revealed that she had lied about owning a food dehydrator, which police later discovered dumped in a rubbish tip, containing traces of the fatal fungi. A computer seized from her house showed browsing history for a website pinpointing death cap mushrooms spotted near her home a year prior to the lunch. Furthermore, the use of individual beef Wellington pastries, when her recipe called for a single, family-sized portion, was scrutinized, with prosecutors suggesting this allowed her to lace other diners' portions while sparing her own.

Experts testified extensively about death cap mushrooms, explaining they are responsible for approximately 90 percent of all fungus-related fatalities globally. These brown-and-white sporing bodies, though easily mistaken for edible varieties and reportedly possessing a pleasant taste, are saturated with deadly chemicals known as amatoxins. These toxins lead to severe symptoms like diarrhea and vomiting, progressing to tissue necrosis, organ failure, and ultimately death if untreated. Native to Europe, death caps have spread to Australia and are typically found growing under oak trees during warm, wet autumn weather.

Adding to the disturbing narrative, Patterson faces fresh allegations of food tampering while working in the kitchen of Melbourne's Dame Phyllis Frost Centre, where she is currently held. A fellow inmate reportedly fell ill after a dispute with Patterson. Corrections Victoria confirmed Patterson had been assigned a kitchen role despite her convictions. This comes after previous allegations that Patterson had attempted to poison her ex-husband, Simon Patterson, on multiple occasions between 2021 and 2022, though no charges were laid in connection to those claims. A tradesman also claimed to have found a "death wall" with ominous messages in Patterson's home. Patterson awaits sentencing, which could result in a life in prison term, with the date yet to be scheduled. Her legal team has 28 days post-sentencing to appeal the convictions and sentence, though they have not indicated if they will do so.