Leongatha mushroom trial: Erin Patterson’s marriage ‘descended to pettiness’

Erin Patterson became ‘extremely aggressive’ after her relationship with her estranged husband, Simon, soured over financial disputes, a court has heard.

Simon Patterson arrives at court to give evidence on Friday. Picture: Luis Enrique Ascui/NewsWire

Triple-murder accused Erin Patterson became “extremely aggressive” after her relationship with her estranged husband, Simon, soured over financial disputes, a court has heard.

Giving evidence in the Victorian Supreme Court on Friday, Simon Patterson agreed that he and Erin “descended into some pettiness” after he refused to pay expenses for their children outside of formal child support.

The court was also told that Mr Patterson was required to pay Erin only $38 a month as part of the ­formal agreement, which he admitted could be considered “unfair” from her perspective.

Ms Patterson is on trial for allegedly murdering her estranged husband’s parents, Don and Gail Patterson, along with Mr Patterson’s aunt Heather Wilkinson, by deliberately serving them poisoned mushrooms at a lunch in Leongatha in mid-2023.

She is also charged with the attempted murder of Heather’s husband, Ian, who was present at the lunch but survived after a lengthy hospital stay. Simon Patterson was invited to attend the lunch, but pulled out the day before.

Ms Patterson has pleaded not guilty to all the charges.

Her case is being heard before the Victorian Supreme Court, which is sitting in the Latrobe Valley Magistrates Court in Morwell, 155km east of Melbourne,

Earlier this week, the court heard that the Pattersons’ relationship turned bitter in late 2022 when she discovered he had categorised himself as separated on his tax ­return. Upon learning this, she ­requested they establish formal child support payments so she could claim family tax benefits.

The jury on Friday was shown a series of messages between the couple in which Mr Patterson refused to pay for their son’s $360 anaesthetist bill because it was outside the child support arrangement.

Ms Patterson wrote to him on November 22, 2022, saying: “Can you please pay this, I paid his surgeon out of pocket fee a couple of days ago”.

Mr Patterson replied: “The department of human services instructed me not to pay you anything for the kids from now on so I cannot pay that, I’m afraid.”

“It’s not paying me it’s paying his anaesthetist,” she responded.

He said: “Yes, that’s exactly the kind of thing they explicitly instructed me not to pay for.”

Around the same time, the court heard, Erin Patterson had messaged Gail and Don Patterson in a group chat that included Simon Patterson, ­requesting that they ­intervene.

In court, Mr Patterson suggested Ms Patterson was being “extremely aggressive” in that group chat, but defence counsel Colin Mandy SC questioned this wording. “You used the word ‘aggressive’ but that’s not the right … that’s not the right way of categorising it, is it?” he suggested.

Mr Patterson responded: “Perhaps you could put up the messages that she messaged the group that I mentioned and we can see.

“I can remember a couple of very perhaps inflammatory messages from Erin to Mum and Dad in the group that I was in about that, so that was obviously very emotive and ongoing,” he said.

But Mr Mandy suggested to Mr Patterson it was “extremely unfair” that he was paying only $38 a month to Ms Patterson in child support because it would not even cover the children’s medical or school fees.

“Looking at it from Erin’s perspective, though, you can see how she might think that that was an extremely unfair position that she was placed in?” Mr Mandy asked.

Mr Patterson replied: “If she knew I was only going to have to pay $30 a month, then I can definitely understand why she’d be very upset, especially if she thought that I knew that she (sic) was going to pay $38 a month.”

Mr Patterson said at the time of the disagreement over the anaesthetist’s fees he did not yet know the cost of child support.

The court also heard Erin was “very, very hurt” after she believed she was not invited to Gail’s 70th birthday celebrations at the local pub. In messages from October 2022 shown to the court, Mr Patterson told her she was being “ridiculous” and his father had invited her to join the rest of the family. At the time, the couple had been separated for about seven years.

“What I reckon is that everybody forgot to actually invite me to this thing and I feel very very hurt by that and your response is to say I’m being ridiculous,” Ms Patterson wrote to Mr Patterson.

He replied, telling her “you can believe what you feel like, but frankly you’re as far off the mark as you possibly could be on this”.

“At this point I can only ask you to consider Mum and her feelings, as she turns 70 tomorrow which is really important to her,” he wrote, asking her to “please respond to Dad’s message accordingly”.

Ms Patterson replied, saying she would attend the lunch and bring their children with her.

Under cross-examination, Mr Patterson said his parents were “really stressed about it”. “They had genuinely believed they had invited Erin to the lunch,” he said.

The court heard Ms Patterson had told her husband about various illnesses she suffered from, including poor mental health, heart arrhythmia and postnatal depression. Mr Patterson said doctors had also told her she may suffer from MS or another chronic illness, which he could not remember. He indicated he had no reason to believe she was lying about these illnesses.

Earlier in the trial, the court heard Ms Patterson pretended to have cancer and allegedly lured the guests to her home for the fatal lunch under the pretence of needing their advice on whether to share the diagnosis with her children.