Deadly mushroom cook weighed fatal dose on kitchen scales, says prosecutor

An Australian woman accused of murdering relatives with beef Wellington documented herself using kitchen scales to calculate a lethal dose of toxic mushrooms, prosecutors allege.

Erin Patterson has pleaded not guilty to killing three people and attempting to murder another at her home in regional Victoria in July 2023. The 50-year-old says she never intended to hurt them and it was a tragic accident.

Prosecutors on Thursday suggested photos found on her phone showing wild fungi being weighed depict her measuring the amount required to kill her guests.

Ms Patterson told the court she had likely taken the photos in question but said she didn't believe the mushrooms in them were death caps.

Ms Patterson's in-laws, Don and Gail Patterson, both 70, along with Gail's sister Heather Wilkinson, 66, all fell ill and died days after the lunch.

Heather's husband, local pastor Ian Wilkinson, was also hospitalised but recovered after coming out of a weeks-long induced coma.

The high-profile trial, which started almost six weeks ago, has already heard from more than 50 prosecution witnesses. Ms Patterson became the first defence witness to take the stand on Monday afternoon.

Under cross-examination from the lead prosecutor, Ms Patterson admitted she had foraged for wild mushrooms in the three months before the July lunch, despite telling police and a health official that she hadn't.

The court was also shown images, taken in late April 2023 and recovered from Ms Patterson's phone, which depicted mushrooms being weighed.

Ms Patterson previously admitted she had repeatedly deleted electronic data in the days following the lunch because she feared that if officers found such pictures they would blame her for the guests' deaths.

Pointing to earlier evidence from a fungi expert who said the mushrooms in the images were "highly consistent" with death caps, Dr Rogers alleged Ms Patterson had knowingly foraged them days before.

She had seen a post on iNaturalist - a website for logging plant and animal sightings - and travelled to the Loch area ten days later on 28 April to pick the toxic fungi, Dr Rogers alleged.

Ms Patterson said she couldn't recall if she went to the town that day, but denied she went there to find death cap mushrooms or that she had seen the iNaturalist post.

"I suggest that you were weighing these mushrooms so that you could calculate the weight required for... a fatal dose," Dr Rogers put to her.

"Disagree," Ms Patterson replied.

The mother-of-two also spoke about putting powdered dried mushrooms into a range of foods like spaghetti, brownies and stew, which prosecutors allege was practice for the fatal lunch.

Ms Patterson said this was not true, but rather an attempt to get "extra vegetables into my kids' bodies".

Prosecutors repeatedly asked her, with different wording each time, whether she had knowingly used the same food dehydrator to prepare death cap mushrooms for the lunch.

CCTV played at the trial shows Ms Patterson disposing of the appliance at a local dump.

"That's why you rushed out, the day after your release from [hospital], to get rid of the evidence," Dr Rogers said.

"No," replied Ms Patterson.

Earlier, Ms Patterson's barrister asked her why she repeatedly lied to police about foraging mushrooms and having a food dehydrator.

"It was this stupid knee-jerk reaction to dig deeper and keep lying," she told the court. "I was just scared, but I shouldn't have done it."

Ms Patterson also repeated her claim that she never intentionally put the poisonous fungi in the meal.

She said the mushrooms used in the beef Wellington may have accidentally included dried, foraged varieties that were kept in a container with store-bought ones.

Ms Patterson was also quizzed on evidence given by other witnesses that she had asked her guests to come to the lunch to discuss health issues, namely a cancer diagnosis.

She said she didn't outright say she had cancer, but still shouldn't have misled her relatives, saying she'd done so partly because their concern made her feel loved.

"I suggest that you never thought you would have to account for this lie about having cancer because you thought the lunch guests would die," Dr Rogers said. "Your lie would never be found out."

"That's not true," Ms Patterson said.

She will resume being cross examined on Friday.