Erin Patterson: Death cap mushrooms located in Loch by retired poisons information specialist, jury told

Erin Patterson allegedly spent time in an area identified to have death cap mushrooms growing in it more than three months before three people fatally ingested the poisonous ingredient while eating lunch at her home, a jury has been told.

The poisonous death cap mushrooms were located 28km from Ms Patterson’s home by a retired pharmacist, who shared the finding online, the triple murder trial was told on Monday.

Ms Patterson, 50, is facing trial after pleading not guilty to the murder of three of her husband’s relatives and attempting to murder a fourth in the country Victorian town of Leongatha.

Prosecutors allege the mother of two deliberately spiked a lunch at her home on July 29, 2023, with death cap mushrooms, while her defence has argued it was an unintentional tragic accident.

On Monday, retired pharmacist and former Victorian Poisons Information Centre poisons information specialist Christine McKenzie gave evidence that she located death cap mushrooms near the township of Loch, about 28km northwest of Leongatha, on April 18, 2023.

Prosecutors allege Ms Patterson’s phone records indicate she “travelled to and remained in the Loch area at around 10 am” the following day, before returning to Leongatha.

Also on April 18, it’s alleged her records indicate she visited Outrim at around 11am, where the jury was told an earlier sighting of death caps were posted on iNaturalist.

Ms McKenzie told the jury she was visiting her daughter and posted the sighting on iNaturalist, a citizen science website used to record species, under the name “Chrismck”.

“We’d been for a walk … my husband and I took our grandson for a walk with the dog,” she said.

She told the court that she observed death cap mushrooms under oak trees at the Loch Recreation Reserve and removed the sporing bodies.

“Initially, the ones I saw first were under a single oak tree,” Ms McKenzie said.

“We had a dog poo bag with us, so I removed all the death cap mushrooms I could find.”

Asked by prosecutor Jane Warren if there was a “risk” the mushrooms could regrow, Ms McKenzie replied “absolutely”.

“More could come up over the subsequent days, weeks,” she said.

Quizzed on if she saw any regrowth, she said she was only visiting Loch for the day.

Under cross-examination by Ms Patterson’s barrister Sophie Stafford, Ms McKenzie agreed she regularly looked out for death cap mushrooms when walking at the reserve.

“I often suspected there would be death cap mushrooms under the oak tree,” she said.

“I’d never seen them previous to that day.”

Ms McKenzie told the jury that she worked for the Victorian Poisons Information Centre for 17 years and developed an algorithm to decide what calls about mushrooms should be escalated to a mycologist to be identified.

“We couldn’t ask every single call about fungi to be identified, there could be hundreds,” she said.

She told the court that she developed a special interest in fungi and undertook further study.

“I became fascinated about how few fungi had been identified in Australia and I find them just personally beautiful,” she said.

Telecommunications expert takes the stand

Next up in the trial is Digital Forensic Sciences Australia’s Dr Matthew Sorrell, an expert in telecommunications systems who told the jury he’d given evidence in more than 400 criminal cases.

Dr Sorrell began giving the jury an overview of how telco company records can track mobile phones through their mobile data usage and connection to cell towers.

“In country areas, there are typically 1-2 base stations that cover a local town,” he said.

“There will also be base stations designed to provide wide area coverage.”

He said mobile phone service will operate through “greediness”, with a phone flicking to different cell towers depending on which provides a better service.

Jurors in the trial were shown a map that depicts cell towers in the Gippsland area at Korumburra, Loch South, Arawata, Kardella and Holmes Hill.

Dr Sorrell will continue giving evidence when the trial resumes at 2.15pm.

Prosecutors allege Ms Patterson intended to kill the lunch guests attending her home after inviting them with the “false claim” of discussing a cancer diagnosis.

“It is the prosecution case that the accused deliberately poisoned, with murderous intent, each … after inviting them for lunch on the pretence that she’d been diagnosed with cancer and needed advice about how to break it to the children,” Crown prosecutor Nanette Rogers SC said at the start of the trial.

Her husband Simon Patterson’s parents, Don and Gail Patterson, both 70, and Gail’s sister Heather Wilkinson, 66, died in hospital in the weeks after the gathering.

Ms Wilkinson’s husband, Korumburra Baptist Church pastor Ian Wilkinson, fell gravely ill but recovered.

Defence barrister Colin Mandy SC told the jury that Ms Patterson did not dispute that the four lunch guests consumed deadly death cap mushrooms at her Leongatha home.

“The defence case is that Erin Patterson did not deliberately serve poisoned food to her guests at that lunch,” he said.

“The defence case is that what happened was a tragedy, a terrible accident.”

The trial, before Justice Christopher Beale, continues.