The following is an edited extract from The Mushroom Murders: A Family Lunch. Three Deaths. What Really Happened? by Greg Haddrick, Allen & Unwin

In a nation such as Australia that values the principle of open justice, it is traditionally held that, following a conviction, all records of the evidence previously deemed inadmissible should be made accessible to the public.

So that everyone can see the way in which the justice system has been fair. Fair to the accused, and fair to the victims.

In the case of Erin Patterson, Justice Beale initially opted not to disclose this pre-trial information to safeguard Erin’s appeal rights. Essentially, if an appeal resulted in a retrial, Erin’s case could be significantly undermined because any prospective juror potentially would have been exposed to all the material that had earlier been considered too prejudicial.

However, this case was unusual due to the unprecedented global interest surrounding it. Almost any potential juror in a retrial scenario would likely have already encountered some information.

That decision was quickly contested by several major global media outlets, arguing that it suggested a conviction wasn’t truly finalized until the appeals process was exhausted. It implied that, after a diligent and thorough jury trial, one remains only ‘convicted-ish’ until the appeal proceedings conclude.

The media emerged victorious. Roughly four weeks subsequent to the jury’s guilty verdict, nearly all of the pre-trial material became public, including Justice Beale’s decisions regarding which evidence was deemed inadmissible and the reasons behind those rulings.

Only one piece of inadmissible evidence remains suppressed. But what was released was sensational.

The media won the day when previously suppressed details about Erin Patterson’s (pictured) plot to kill her husband Simon were made public 

Mushroom cook Erin attempted to poison her estranged husband Simon (pictured) at least three times – on one occasion refusing to take him to hospital when he asked to go.

It included the details around the three attempted murder charges that were dropped on the eve of the trial. In fact, the Office of Public Prosecutions was ordered by the Court of Appeal to ‘sever the indictment’ – meaning that those charges would have to be heard at a separate trial – and then it was decided to drop the attempted murder charges altogether.

Under the appeal court’s ruling, ‘coincidence evidence’ about an accused person (evidence of a similar crime) ‘cannot be used against the accused unless the probative value of the evidence substantially outweighs any prejudicial effect it may have on the accused’.

These were the three attempted murder charges that were excluded from Erin’s trial because the judge considered them to be ‘coincidence evidence’.

Charge 1:

In November 2021, Erin had suggested she and Simon should go on a hiking trip to Wilsons Promontory without the kids. On Tuesday, 16 November 2021, Erin went to Simon’s house to pack for the trip and she gave him a Tupperware container of penne bolognaise. Simon ate it that night and the next morning started vomiting. He continued to vomit and suffer diarrhoea as they drove to Wilsons Promontory.

They stayed in an Airbnb and Simon wanted to go to hospital, but Erin advised against that, saying it would be such a long wait.

Finally, on 19 November, Erin drove Simon back to Gippsland and took him to Leongatha Hospital. He was diagnosed with severe dehydration and acute renal impairment with modestly elevated lactate; he was then transferred to Monash Medical Centre, where he remained until 27 November 2021.

Extensive testing by medical staff at the time could not determine the underlying cause of his illness.

Don and Gail Patterson (pictured) died after being served beef Wellington by their daughter-in-law Erin Patterson. The dish was laced with poisonous death cap mushrooms 

Erin Patterson was sentenced to life in prison with no chance of parole for 33 years for the triple murder 

Charge 2:

A few months later, Erin suggested that she and Simon should plan another camping trip without the kids since the previous one hadn’t worked out. Simon agreed, and they planned a trip to Howqua, about 130km northeast of Melbourne. On 24 May 2022, they were camping at Howqua when they ate chicken korma curry that Erin had prepared and packed in separate containers. 

The next day, Simon vomited and had diarrhoea all morning. Erin drove him to Mansfield Hospital, stopping along the way so he could vomit.

They then drove home. But by 29 May, Simon’s condition had only got worse and he asked Erin for help. She went to his house and called an ambulance, which took him to Casey Hospital in south-east Melbourne. 

Here he was admitted in a state of haemodynamic shock. He had lactic metabolic acidosis; multiple organ failure; and markedly elevated lactate levels, which suggested liver ischaemia. 

A blood film test was consistent with severe sepsis. He was intubated and admitted to intensive care in an induced coma. Again, doctors were unable to determine the cause of his illness.

He was in that induced coma for sixteen days – until 14 June – and on 22 June he was transferred to a rehabilitation centre, where he remained until 8 July. After that, he underwent weekly blood tests to see if the cause of his illness could be determined.

During that time, Erin was moving out of Shellcot Road and into her brand-new house in Leongatha. Simon was in hospital the whole time.

On 22 July, Erin prepared a beef stew with rice, which both she and Simon ate for lunch. The next morning Simon became ill again with vomiting and diarrhoea. Miraculously, Erin was fine. But Simon went straight to Leongatha Hospital and was transferred to Monash Medical Centre (again), where he remained for several days. This incident was considered part of the ‘second attempted murder’.

Charge 3:

On 6 September 2022, Simon and Erin went for another walk around Wilsons Promontory. Erin had brought them pre-prepared lunches, each one separately wrapped.

Again, shortly after lunch, Simon started to vomit and feel unwell. Erin drove him to Don and Gail’s house, and they called an ambulance. Simon suffered a seizure and was in a reduced conscious state. He was admitted to the Casey Hospital intensive care unit and was intubated again; he was discharged on 9 September.

This happened just before the disagreement between them over child support payments, when Erin thought Simon was unreasonable and vindictive.

And why was all this ruled inadmissible? On each occasion, there was no clear evidence or proof that Erin had deliberately caused Simon’s illness with her meals. It just looked that way in hindsight, given what happened on 29 July 2023. 

However, once it was determined that Erin’s lunch guests on 29 July had been deliberately poisoned by death cap mushrooms in the beef Wellingtons she made for them, then it looked almost certain that that had happened in these earlier cases, too. But as that had not been determined yet, these episodes could not be presented as evidence.

Why couldn’t the law let a jury see all this and just explain it to them? At the beginning of a trial, a jury is told, ‘You are the judge of the facts.’ But what the law is really saying is, ‘You are only the judge of a particular set of facts that we trust you to make a fair decision on. We can’t trust you with all these other facts. You might be prejudiced.’

What do those other attempted murder charges mean?

It might have been hard to gain a conviction on those charges alone. In each of the three charges, no clear medical evidence directly and deliberately connects Simon’s illness to the meals Erin prepared. But they did at least answer one huge question. How on earth Erin ever thought she could get away with lacing food with poison?

The answer is now clear to see: because she already had.

Three or four times before.

On all previous occasions, for whatever combination of reasons, she had outsmarted the medical profession. Why would she think her beef Wellington lunch would be any different?

Those dumb doctors were never going to figure out what had happened. They hadn’t in the past, and they wouldn’t now.

Greg Haddrick’s new book tells the fascinating inside story of the triple murder trial that had the entire world gripped