One of Australia’s most high-profile murder cases has returned to the courts this week, as Erin Patterson — the 51-year-old woman convicted of poisoning three of her relatives with toxic death cap mushrooms in 2023 — challenges her life sentence, while state prosecutors separately push for a harsher punishment.
Patterson was found guilty of orchestrating a fatal poisoning at her regional Victoria home, where she served guests a beef Wellington laced with death cap mushrooms during a family lunch. The attack killed her 70-year-old in-laws Don and Gail Patterson, and Gail’s 66-year-old sister Heather Wilkinson. Heather’s husband Ian Wilkinson, the only person who ate the meal and survived, was present in the Melbourne Court of Appeal for the first day of hearings on Wednesday. Patterson herself did not appear in person, instead joining the proceeding via video link from her prison, where she is currently serving her life sentence. Her estranged husband Simon Patterson — who avoided the lunch by cancelling at the last minute, having long suspected his wife was attempting to poison him — was also absent from the court.
The most serious allegation raised by Patterson’s legal team centers on a serious procedural error during the original trial: while the jury was deliberating on a verdict, all jurors were housed in the same hotel as the prosecution team, a key police witness, and reporters covering the case. Patterson’s senior barrister Richard Edney labeled the incident a “catastrophic” breakdown in procedure that irreparably damaged the integrity of the guilty verdict, arguing the convictions must be overturned and a full retrial ordered. “Justice must not only be done, it must be seen to be done,” Edney told the court.
Representing the state, Director of Public Prosecutions Brendan Kissane acknowledged the overlapping accommodation was regrettable, but stressed it was an unintended accident, not a deliberate breach of procedure. He added that no evidence has emerged to prove any improper communication occurred between jurors and the prosecution or witness, meaning the incident does not qualify as a fundamental trial irregularity that would justify overturning the verdict.
Beyond the hotel mix-up, Patterson’s legal team has outlined multiple other grounds for appeal. They argue that prosecution speculation linking Patterson to the foraging of death cap mushrooms should never have been presented to the jury. Prosecutors had argued during the original trial that Patterson targeted the mushrooms after finding reports of local death cap sightings on the citizen science platform iNaturalist, pointing to cell tower data that placed her phone in the areas where the mushrooms were spotted. But defense lawyer Veronika Drago told appeal judges the prosecution had inflated thin, circumstantial evidence into an incriminating narrative. Drago noted there is no proof Patterson ever accessed or viewed the iNaturalist posts, and the cell tower data only provides a possible location, not definitive proof of her presence. “Speculation was invited by the prosecution,” she said, arguing the unfair prejudice of the evidence far outweighs any limited value it could have had. Crown prosecutor Jeremy McWilliams pushed back against this claim, defending the use of cell tower expert testimony and noting the jury was properly permitted to use that evidence to assess whether Patterson had the opportunity to source the toxic mushrooms as alleged.
The defense also argues that damaging Facebook messages Patterson sent months before the lunch, in which she harshly criticized her estranged husband and his parents, were irrelevant to the case and should have been excluded from trial. They further claim the original chief prosecutor engaged in overly aggressive, improper conduct during cross-examination, and identify 35 separate issues with the prosecution’s closing address to the original jury. When Justice Peter Kidd, one of the three appeal judges, asked why these issues were not raised during the original trial, Edney explained that the original defense team was operating under intense time and pressure, and the additional issues only became clear once the dust settled after the verdict.
In pre-hearing filings, prosecutors have rejected all of the defense’s claims, arguing the guilty verdicts were inescapable given the overwhelming body of evidence. They noted multiple incriminating circumstances: the suspicious arrangement of the lunch invitation, Patterson’s decision to serve her own meal on a separate plate from the guests, and the fact that Patterson suffered no adverse health effects while all other guests became seriously ill. “Taken together, these circumstances point overwhelmingly to a deliberate act of poisoning,” prosecutors said.
The appeal hearing is set to continue on Thursday, where prosecutors will continue responding to the defense’s arguments, and will also bring forward their own appeal against Patterson’s sentence. Currently, Patterson is eligible to apply for parole after serving 33 years of her life sentence, but the Director of Public Prosecutions argues this parole period is manifestly inadequate, and says the original trial judge acted inappropriately by setting any fixed parole term. The three appeal judges have indicated they will reserve their decision after concluding the hearing, meaning a ruling on the appeals is not expected for many weeks.