Erin Patterson, convicted of triple murder, is appealing her conviction on seven grounds. Patterson, 51, was sentenced to life in prison in September, with a non-parole period of 33 years. She was found guilty of murdering her former in-laws, Don and Gail Patterson, both 70, and Gail's sister, Heather Wilkinson, 66. The jury determined that Patterson intentionally served beef Wellingtons containing toxic death cap mushrooms during a lunch at her home in Leongatha, Victoria, in July 2023. She was also convicted of the attempted murder of Heather's husband, Ian Wilkinson, 69, who became seriously ill but survived.

Patterson's legal team filed a formal appeal application with the Supreme Court, which was made public on Wednesday. Among the claims, Patterson argues that there was a "fundamental irregularity" during jury deliberations. It was revealed that the jury stayed at the same hotel as a police informant and two members of the prosecution team. The appeal documents state, "That has fatally undermined the integrity of the verdicts and requires the quashing of the convictions and an order for a re-trial so that justice cannot only be done but be seen to be done."

Justice Christopher Beale, who presided over the trial, previously stated that the jury had a separate floor in the hotel, isolating them from other guests. Patterson also contends that she experienced "unfair and oppressive" cross-examination during her testimony, which lasted several days. She claims that the prosecution's opening and closing arguments implied a motive for the murders, despite the prosecution not presenting a motive during the trial.

Additionally, Patterson's appeal challenges the admissibility of certain evidence. She argues that evidence related to cell towers and sightings of death cap mushrooms, as well as information from social media, should not have been allowed in court. Patterson also claims that Justice Beale erred by ruling that photos and videos of mushrooms found on an SD card at her home were inadmissible.

Throughout the trial, Patterson maintained her innocence, asserting that the incident was a tragic accident. In a separate development, Crown prosecutors have also filed an appeal regarding Patterson's sentence, arguing that it is "manifestly inadequate." Justice Beale noted that Patterson's actions represented a severe betrayal of trust, yet he granted her the possibility of parole, citing her solitary confinement for at least 22 hours a day.

Acting Director of Public Prosecutions Diana Piekusis KC criticized the judge's decision, claiming he erred in suggesting there was a "substantial chance" Patterson would remain in solitary confinement for an extended period. While the court has accepted Patterson's notice of appeal, it must first grant her permission to proceed before the case can be heard.