An Australian woman convicted of poisoning three relatives with deadly mushrooms had her appeal rejected on Friday and her sentence increased to life in prison with no possibility of parole.

Erin Patterson (52) was found guilty last year of murdering her husband’s parents and aunt in 2023, deliberately lacing a beef Wellington lunch with death-cap mushrooms at her home in rural Victoria state.

The Court of Appeal in Victoria dismissed her bid to have the convictions quashed, finding her “carefully planned and deliberate” killings deserved a harsher punishment than the one originally handed down.

“This offending was extraordinarily cold and calculated,” judge Stephen McLeish said.

“It stands to be denounced in the strongest terms.”

Patterson had argued her triple murder convictions amounted to a “miscarriage of justice”, urging the court to either set her free or order a retrial.

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Her lawyers cited a string of irregularities during the 11-week trial, among them jurors and prosecution members staying in the same hotel as a police witness.

They also took issue with what they called an “oppressive” cross-examination and unfair rulings on the admission of evidence.

Originally sentenced to life in prison with eligibility for parole after 33 years, Patterson watched proceedings via video link from a maximum-security prison on the outskirts of Melbourne.
Prosecutors had argued the original non-parole period was “manifestly inadequate”.

“Indeed, our submission is that for this offending the respondent should be sentenced to life without parole,” Director of Public Prosecutions Brendan Kissane told an appeal hearing earlier this year.

The court agreed. Highlighting Patterson’s “shocking criminality”, McLeish ruled she should serve the rest of her life behind bars with no prospect of release.

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Patterson hosted four people for lunch at her rural Victorian home in July 2023, serving beef Wellington smothered in mushrooms.

Her guests were Don and Gail Patterson, the parents of her estranged husband Simon, along with his maternal aunt Heather Wilkinson and her husband Ian, a local Baptist pastor.

Don, Gail and Heather died of organ failure within a week. Ian fell gravely ill but survived.

A jury found Patterson had deliberately laced the meal with death-cap mushrooms, a variety easily mistaken for edible fungi that reportedly carry a sweet taste concealing their lethal potency.

Patterson maintained the contamination was accidental.
The case drew intense interest around the world. Patterson’s trial attracted podcasters, film crews and true crime enthusiasts to a courthouse in Morwell, a rural Victorian town, generating more publicity than almost any other Australian criminal case in recent memory.

Although the case exposed various tensions within Patterson’s family a motive for the killings has never been established.