Woman who held deadly lunch that killed three accidentally exposed her own lies with resurfaced Facebook posts

It's been nearly two years since Australian woman Erin Patterson cooked her former in-laws a lunch that would go on to kill three of them and leave the fourth seriously injured.

Patterson, 50, who hails from Leongatha, Australia, has been charged with three counts of murder and one count of attempted murder, after her estranged husband’s family died from eating death cap mushrooms, which can be fatal even when consumed in small amounts.

The tragic ordeal, which took place in July 2023, began after Patterson invited her former in-laws Gail and Don Patterson, as well as Gail's sister Heather Wilkinson and Heather's husband Reverend Ian Wilkinson, to have lunch at her home.

The meal she had prepared, a beef wellington, made all four guests ill, with Mrs Wilkinson and Mrs Patterson both passing away, while Mr Patterson died the next day.

Mr Wilkinson, however, miraculously survived after weeks of treatment and a liver transplant in hospital.

Patterson had also invited her ex-husband, Simon Patterson, to the meal but he pulled out at the last-minute saying he 'felt too uncomfortable' to attend the lunch alongside his parents, aunt and uncle - a move which would go on to save his life.

Now, in her trial, which commenced earlier this week, it was discussed that a food dehydrator with Patterson's fingerprints was found dumped at a rubbish site, and prosecutors alleged it was used to prepare the mushrooms.

Patterson's previous Facebook posts have also been pulled up in regards to the dehydrator.

Erin Patterson is on trial for three murder charges and one of attempted murder (9News)

In a written statement to police earlier in August of 2023, Patterson addressed speculation that police had seized a food dehydrator at the local tip while investigating the case.

She admitted that she lied to the police when she told them the kitchen gadget had been dumped at the tip a 'long time ago' - before revealing that her ex had asked a chilling question at the time.

Patterson recalled how she had been at the hospital with her children 'discussing the food dehydrator' when her ex-husband asked: "Is that what you used to poison them?"

She explained that she started to feel concerned she might lose custody of her children, so panicked and ended up dumping the dehydrator.

"I now very much regret not answering some questions following this advice given the nightmare that this process has become," Patterson added at the time.

However, at her trial, Patterson's lawyer, Colin Mandy SC, confirmed that she had previously lied about the dehydrator.

Patterson's lunch killed three people and left the fourth seriously injured (Evgeny Rukinglaz / Getty Images)

Prosecutor Nanette Rogers SC said in her opening submissions that Patterson told police she had never owned a food dehydrator nor dehydrated food, but then said she may have owned one years ago.

Patterson had, in fact, been sharing several snaps of the dehydrator and documenting her habit of using it to dehydrate mushrooms with Facebook friends she met on a group dedicated to discussing the case of convicted baby killer Keli Lane.

CCTV footage later showed Patterson ditching a dehydrator at a local tip with forensic analysis later revealing that it had her fingerprints on it and contained traces of death cap mushrooms.

The disposal of the dehydrator had been done to conceal her actions, Rogers said.

Patterson has denied all the charges against her.