Erin Patterson's ‘cat and mushrooms’ Facebook post revealed in pre-trial bombshell

A tense silence fell over a small rural court room as Erin Patterson, facing a jury and fiddling with her fingers, delivered the first of many admissions.

“Did you have an interest in wild mushrooms?” defence barrister Colin Mandy SC asked on the killer’s second day in the witness box.

“Yeah, I did,” the 50-year-old replied.

The jury listened intently as she admitted a love of mushrooms and wild fungi for the first time in week six of her triple-murder trial.

But little did they know the evidence that was not aired.

Media were banned from reporting on pre-trial evidence that Justice Christopher Beale had ruled out of the trial to give Patterson time to lodge an appeal.

A suppression order over that material was lifted on Friday.

One of the most bizarre pieces of evidence that did not make it to the trial was a Facebook post to a poisons help page.

Prosecutors alleged Patterson uploaded a photo of a cat eating mushrooms about 18 months before Simon claimed he was first poisoned by his estranged wife, in November 2021.

“My cat chewed on this mushroom just now,” the post said, according to pre-trial evidence.

“He is having a vomit. Was in grassland near trees, I’m in Victoria Australia.”

Patterson owned a dog but did not own a cat.

Prosecutors alleged the post was fake and they planned to use it in the trial to show the killer’s long-held interest both in poisons and wild mushrooms.

Jane Warren said it showed that Patterson’s interest in mushrooms was “in the poisonous properties”.

Defence successfully argued against the post being permitted as evidence in the triple-murder trial.

“The prosecution is at pains to establish the accused did not have a cat and therefore that this post was dishonest,” barrister Colin Mandy SC told a pre-trial hearing.

“That will reflect poorly on the accused if that’s admitted to evidence.”

The post might have been manipulated by the person who provided it to police, Mr Mandy said as he argued they should have been called to give evidence in the trial.

“The witness who produced the screenshot had previously manipulated screenshots in the Facebook group using Photoshop,” the defence barrister said.

“Its reliability on the face of it is questionable.”

Ultimately, Justice Beale ruled it out of evidence before the trial began.

A number of other items of evidence revealed Patterson’s alleged penchant for poisons.

These were found by Victoria Police digital officers, who trawled through thousands of pieces of data found on devices seized from Patterson’s home.

The digital investigators used key words including “death”, “mushroom” and “poison”.

An appendix from a 2007 book called Criminal Poisonings was found on a Samsung tablet.

It listed the colour, odour, solubility, taste and lethal dose of poisons including antifreeze, arsenic and cyanide.

Prosecutors alleged in pre-trial hearings that Patterson had access to the document in October 2019.

However, defence lawyers successfully argued prosecutors could not prove she accessed the file just because it was found on the device as there was no evidence she had downloaded it or read it.

Mr Mandy said it would be prejudicial to Patterson in her trial and claimed Patterson’s children might have been using the tablet when the file was downloaded.

“And 2019 is too remote to be relevant to these allegations,” Mr Mandy told pre-trial.

Another PDF titled “an overview of fungi in Melbourne” was found on a device at Patterson’s home with an unknown date. But the defence claimed it had limited probative value as it did not mention poisonous mushrooms.

The document had death cap mushrooms on the second page.

“There’s lots of people who are widely read, but don’t read about poisonous mushrooms,” Justice Beale commented on the document.

The jury was told about Patterson ditching the dehydrator she used to dry out the deadly mushroom after she left Melbourne’s Monash Hospital on August 2, 2023.

However, they were not told about her first visit to Koonwarra transfer station - on the same day as the beef Wellington lunch - where she disposed of cardboard.

Prosecutors told pre-trial hearings that Patterson was seen going to the tip on July 29, 2023.

She also put her rubbish bins out for collection on the day of the lunch - which prosecutors alleged was incriminating conduct - but the jury was not told that either.

Patterson was ultimately found guilty in July of three counts of murder and one of attempted murder over the poisoned beef Wellington meal.

Her in-laws Don and Gail Patterson, and Gail’s sister Heather Wilkinson all died following the lunch, while Heather’s husband Ian Wilkinson became seriously ill but survived.