Two years ago, Erin Patterson’s lunch guests were admitted to hospital. This week she became a convicted murderer

The mushroom murder trial attracted so much attention that Morwell, where the court is located, and nearby Traralgon received an economic boom. And then it was over

It’s a case so well-publicised it barely needs introduction. Erin Patterson, a middle-aged mother of two, hosted a lunch at her home in Leongatha, a regional town in the Australian state of Victoria, on 29 July 2023.

After being served individual beef wellingtons laced with death cap mushrooms, three of her relatives died and one barely survived.

After a two-and-a-half month trial that made global headlines, Patterson was on Monday found guilty of murdering her parents-in-law, Don and Gail Patterson, and Gail’s sister, Heather Wilkinson, and attempting to murder Heather’s husband, Ian Wilkinson.

“Guilty, guilty, guilty, guilty,” the jury’s foreperson read in quick succession.

Patterson didn’t flinch. She looked straight at the jury, her face unreadable. It was all over within minutes.

Patterson’s lawyers, led by Colin Mandy SC, left the courtroom without making comment. The lead prosecutor, Nanette Rogers SC, wasn’t even there. There were no members of the Wilkinson or Patterson families in courtroom four to hear the verdict, either. Just one friend of Erin Patterson’s, quietly wiping away tears.

It was a sudden end to a trial that lasted more than 10 weeks, featured in excess of 50 witnesses and was forensically covered by the biggest media contingent to follow Victorian supreme court proceedings in recent history.

According to the supreme court, more than 250 journalists registered for updates on the trial. Nine authors, seven podcast producers, seven documentary crews and a television drama series were among those who attended Latrobe Valley law courts, alongside court watchers and the victim’s families.

The media circus contributed to an economic boom in both Morwell, where the court is located, and Traralgon, the biggest town in the region and where most visitors stay.

Throughout the trial, there was no dispute that Patterson had served a lunch containing death cap mushrooms that killed three of her guests and made the fourth seriously ill. But had she meant to poison them?

Her lawyers had argued it was a tragic accident. They said when the lunch turned deadly, Patterson panicked and lied to police, saying she had never foraged for mushrooms.

Prosecutors offered another narrative: Patterson deliberately poisoned her lunch guests “with murderous intent” and then attempted to cover it up.

They did not provide a motive, nor is one required by law. But the court heard that Erin and Simon Patterson’s relationship was punctuated by repeated ruptures and reconciliations after their 2007 marriage, until they separated permanently in 2015.

The split, which was not formalised through divorce, was amicable, Patterson’s estranged husband told the court, until about October or November 2022, when he said a miscommunication between himself and his accountant resulted in him being listed as “separated” on a tax return form for the first time.

In a message shown to the court, Erin wrote it had family tax benefit and child support implications that could cost her up to about $15,000 a year.

Simon told the court he was advised by child support authorities not to pay any expenses relating to the children, including school and medical fees, while the amount he had to pay in child support was calculated.

It spelled an end to their “chatty” relationship. Simon said Erin became “extremely aggressive”.

In a series of messages written in December 2022, Erin told friends she was disappointed Simon’s parents would not help mediate the dispute.

“[Don] said they can’t adjudicate if they don’t know both sides … This family I swear to fucking god,” one message read. Others said she wanted “nothing to do” with her parents-in-law, that she was “sick of this shit” and “fuck em”.

Six months later, she invited them to lunch. Simon also agreed to go, but the night before the lunch he texted her to cancel, saying he felt “too uncomfortable”.

Patterson replied: “That’s really disappointing. I’ve spent many hours this week preparing lunch for tomorrow which has been exhausting in light of the issues I’m facing and spent a small fortune on beef eye fillet to make beef wellingtons because I wanted it to be a special meal, as I may not be able to host a lunch like this again for some time.”

Ian Wilkinson told the court he recalled Patterson plating the individual beef wellingtons on four large grey plates and a smaller plate – an “orangey, tan” colour. Patterson, he said, ate from the odd plate.

After the group had finished eating, Patterson “announced that she had cancer”, the Korrumburra Baptist church pastor said.

“In that moment, I thought, ‘This is the reason we’ve been invited to lunch’,” he said.

Patterson’s four guests all were admitted to hospital the next day.

Taking to the witness box herself, Patterson admitted she had never been diagnosed with cancer. She said she had told the lie as she was embarrassed about her plan to undergo gastric bypass surgery for weight loss. It later emerged in court that the clinic where she said she had an appointment offered no such surgery, with Patterson saying she must have been mistaken in her evidence, though it did offer liposuction.

She said she was a binge eater who had struggled with her body image since she was a child. On the day of the lunch, she said she binge ate two-thirds of an orange cake brought by Gail, then vomited it up – a plausible explanation, the defence said, for why she was less unwell than her guests later.

Much of the trial centred around Patterson’s actions after the lunch. She refused treatment on her first presentation at Leongatha hospital and discharged herself against medical advice; was reluctant for her children to be taken to hospital for assessment after she said they had eaten leftovers of the lunch; disposed of a food dehydrator she had used to dry mushrooms; lied in a police interview; and performed a series of factory resets on one of her mobile phones. Another phone, believed to be primarily used by Patterson, was never found by police.

The prosecution said Patterson told so many “lies upon lies” that it was “hard to keep track of them”.

“When she knew her lies had been uncovered, she came up with a carefully constructed narrative to fit with the evidence – almost. There are some inconsistencies that she just cannot account for so she ignores them,” Rogers said.

She said the jury should have “no difficulty” in rejecting the argument that “this was all a horrible foraging accident”.

They did just that.

Now a convicted triple murderer, Patterson will face a sentencing hearing later this year. Her lawyers will have 28 days from the date of her sentence to decide if they are going to appeal.

If an appeal does proceed, the saga that has gripped the globe will continue.