Erin Patterson murder trial told dangerous death cap mushroom sighted near her home

Court told mushroom expert logged photos and GPS coordinates on a citizen science website

An internationally recognised mushroom expert told the court on Tuesday that he discovered the poisonous mushroom near the house where Erin Patterson lived during the triple murder trial that has gripped Australia.

Dr Thomas May, a mycologist or scientist specialising in fungi, took the witness stand on Tuesday with pictures of various types of mushrooms and the remains of the fateful beef wellington meal taking the centre stage.

Ms Patterson ,50, is accused of serving a meal laced with deadly mushrooms that killed her former husband’s father, mother and aunt – Don Patterson, Gail Patterson, and Heather Wilkinson – and left his uncle, Ian Wilkinson, critically ill.

Ms Patterson, who is from Victoria, denies the charges of murder and attempted murder brought against her. She insists the poisoning was a tragic accident.

Dr May told the court that the sightings of death cap mushrooms were recorded near Ms Patterson’s home in Leongatha in April and May 2023.

He said he submitted a post about the sightings of the dangerous mushrooms in the Loch and Outtrim areas of Leongatha on the iNaturalist website on 21 May 2023 after spotting and picturing the fungi on a walk.

Ian Wilkinson (R), the only surviving guest of a lunch at Erin Patterson's house, leaves after testifying at a Supreme Court sitting at the Latrobe Valley Courts in Morwell, Victoria (EPA)

The jurors were shown a screenshot image of the post from his profile under the name “Funkey Tom”.

The court was previously told by prosecutors that Ms Patterson visited Loch on 28 April and Outtrim on 22 May, citing her phone records.

The lunch after which three people lost their lives happened on 29 July 2023.

Dr May said that the death cap mushrooms were most commonly found in the month of May and varied in colour but always grew around oak trees.

"There are certainly some mushrooms that occur in Victoria that are quite similar (in appearance) to the death cap," he said.

"I put a very precise latitude, longitude geocode in the location," he told the court about his post on the website.

The death cap mushrooms are at the centre of the trial after the court was told that the mushrooms were part of the paste that was used to make the beef wellington main course served to her guests. Doctors confirmed that the four guests who ate the dish suffered from Amanita phalloides poisoning, with only one surviving after long treatment at a hospital.

An exterior view of the Leongatha home where Erin Patterson allegedly served the death cap mushroom-laced lunch (EPA)

These mushrooms, known by their scientific name, Amanita phalloides, are among the most poisonous and have been involved in the majority of human fatal cases of mushroom poisoning. These were first reported in Australia in the 1960s.

Dr May said these mushrooms were European species that now grow in places including Australia, New Zealand and the United States.

He said these mushrooms, however, did not grow in China after Ms Patterson reportedly said she sourced the mushrooms from an unspecified Chinese or Asian grocer in Melbourne.

The defence of Ms Patterson on Tuesday showed a dozen photos of various types of mushrooms to Dr May and challenged him to guess which ones were poisonous.

Dr May was shown 10 photos of mushrooms, which he identified as likely death caps. On Tuesday, Dr Varuna Ruggoo, an emergency physician at Monash Health where Ms Patterson was assessed said she seemed “clinically well” two days after the lunch.

She said she administered IV fluids and N-acetyl cysteine (NAC) to Ms Patterson for potential liver issues on 1 August 2023.

“She appeared clinically well. In a normal mood and affect,” the doctor told the court.