An Australian mother has been found guilty of murdering her estranged husband's parents and an aunt by serving them a beef Wellington laced with poisonous mushrooms.

Erin Patterson, 50, invited her former parents-in-law, Don and Gail Patterson, both 70, and Gail Patterson's sister, Heather Wilkinson, 66, to the fatal lunch on 29 July 2023.

All four fell ill after eating a meal of beef wellington, mashed potatoes and green beans at Patterson's home in the town of Leongatha, the court was told.

Prosecutors said Patterson knowingly laced the beef pastry dish with deadly death cap mushrooms, also known as Amanita phalloides, at her home.

The guests ate their meals off four large grey dinner plates, while Patterson ate from a smaller, tan-coloured plate, the court heard.

Mrs Wilkinson and Mrs Patterson died on Friday, 4 August 2023, while Mr Patterson died a day later.

Reverend Wilkinson spent seven weeks in the hospital but survived.

Her estranged husband, Simon Patterson, with whom she has two children, was also invited to the lunch and initially accepted but later declined, the trial heard.

The jury was told that prosecutors had dropped three charges that Patterson had attempted to murder her husband, whom she had been separated from since 2015.

Reverend Wilkinson said that immediately after the meal, Patterson fabricated a cancer diagnosis, suggesting the lunch was put together so that she could ask them the best way to tell her children about the illness.

The prosecution said she did this to justify the children's absence.

The defence did not dispute that Patterson lied about having cancer.

The trial attracted intense interest in Australia, with podcasters, journalists and documentary-makers descending on the town of Morwell, around two hours east of Melbourne, where the court hearings took place.