Mushroom trial week 4: Phone towers, poison and CCTV

The murder trial of Erin Patterson - the Victorian woman who denies poisoning her former in-laws with a beef Wellington allegedly laced with death cap mushrooms — has now completed its fourth week. Australia Correspondent Aziz Al Sa'afin recaps the key moments from the proceedings.

Poisons expert Christine McKenzie told the court she spotted death cap mushrooms growing in Loch, Victoria, in April 2023 and uploaded photos to iNaturalist - the same citizen science site used by mushroom expert Dr Thomas May earlier in the trial.

She said she removed the mushrooms to stop anyone mistaking them for edible fungi but didn’t return to the site, so couldn’t rule out whether more had grown back.

Telecommunications expert Dr Matthew Sorell explained how mobile phone towers connect to devices and how signal data can be interpreted.

The prosecution presented maps showing a phone registered to Patterson had connected to towers in Loch and Outtrim on May 22, 2023 shortly after death caps were reported in the area.

Prosecutors argue she travelled there in response to the online mushroom sightings. But under cross-examination, Dr Sorell conceded phone records can be imprecise with terrain - weather and congestion all affecting signal data.

The jury was shown new CCTV from July 30 - the day after the fatal lunch - showing Patterson at a BP service station in Caldermeade.

In the footage, she walks through the store, briefly enters the toilet for nine seconds and appears to browse for items.

Detective Senior Constable Khuong Tran told the court he had been tasked with retrieving the footage as part of the investigation.

The footage lines up with earlier testimony that Patterson had driven her son to a flying lesson that day, and had complained to hospital staff of vomiting and diarrhoea following the lunch.

A police digital forensic officer told the court that a computer seized from Patterson’s home had been used to search for the locations of poisonous mushrooms prior to the fatal lunch.

One search accessed an iNaturalist page showing death cap sightings in Moorabbin in 2022, followed by a Google search for a nearby pub.

The jury also heard from a Monash City Council officer who investigated where the mushrooms might have come from. He inspected multiple stores across Melbourne. Most mushrooms were commercially packaged, but one store was found to be selling repackaged varieties though they didn’t match those Patterson is alleged to have used.

Further digital evidence was presented, including messages from a Facebook group chat where Patterson allegedly described frustrations with her estranged husband, calling him a “deadbeat”, and referenced tensions with his parents, who she’s accused of murdering.

Investigators also recovered images from a Samsung tablet taken from her home, showing mushrooms placed on kitchen scales, as well as search history related to cancer. The court heard one of Patterson’s phones had been factory reset four times in 2023 including three times after the deadly lunch.

Photos of a food dehydrator, which the prosecution alleges may have been used to prepare the poisonous mushrooms were also shown to the jury.

The trial continues. Patterson denies all charges.