Homicide squad detectives charged Erin Patterson on November 2 with three counts of murder and five counts of attempted murder over a poisonous mushroom lunch.
Patterson was remanded in custody to appear at Latrobe Valley Magistrates' Court in Victoria on November 3.
Victoria Police said the murder charges and two attempted murder charges "relate to an incident on July 29 where four people were taken to hospital after they fell ill following a meal at a private residence in Leongatha".
A 70-year-old man, a 70-year-old woman and a 66-year-old woman, all from Korumburra, subsequently passed away.
A 69-year-old Korumburra man was released from hospital on September 23, police said.
Police said the further three attempted murder charges relate to three separate incidents in Victoria between 2021-2022.
It's alleged a 48-year-old Korumburra man became ill following meals on these dates.
Detective Inspector Dean Thomas said "over the last three months, this investigation has been subjected to incredibly intense levels of public scrutiny and curiosity.
"I cannot think of another investigation that has generated this level of media and public interest, not only here in Victoria but also nationally and internationally."
The charges follow police investigations at the Leongatha home on November 2 where technology detector dogs used by the Australian Federal Police were deployed.
Ms Patterson's charges follow the deaths of three lunch guests invited for a home-cooked meal on July 29.
Don and Gail Patterson, Ms Patterson's former parents in-law, and Gail's sister Heather Wilkinson died in hospital days after eating the mushroom meal.
Mrs Wilkinson's husband Ian was also hospitalised.
He was released in late September and "continues to recover", detective inspector Thomas said.
Ms Patterson said she did not know the beef Wellington allegedly contained poisonous death cap mushrooms.
In statement made on August 14, two weeks after the lunch, she said if people "understood the background more, they would not be so quick to rush to judgement".
"I am now wanting to clear up the record because I have become extremely stressed and overwhelmed by the deaths of my loved ones," she said.
"I am now devastated to think that these mushrooms may have contributed to the illness suffered by my loved ones. I really want to repeat that I had absolutely no reason to hurt these people whom I loved."
Ms Patterson said the meal was made with a mixture of button mushrooms from a major supermarket chain and dried mushrooms from an Asian grocery store in Melbourne.
When asked to identify the specific shop in Melbourne where the dried mushrooms were bought Ms Patterson said she was unable to.
In her statement, Ms Patterson said she portioned the meal onto plates and let her guests pick their own.
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On July 29 Ms Patterson and her four guests ate beef Wellington at the Leongatha home.
Ms Patterson said her two children skipped lunch and went to a cinema.
Leftovers were served to the kids on July 30 but Ms Patterson said the allegedly poisonous mushrooms had been scraped from the dish due to their fungus aversion.
Ms Patterson and her four lunch guests presented at hospital complaining of stomach pains on July 30.
Monash Medical Centre confirmed Ms Patterson had been treated with a liver drug after she was transferred to the metro hospital on July 31.
Police found Ms Patterson's food dehydrator at the tip as Gail Patterson and Heather Wilkinson died in hospital on August 4.
Don Patterson died the following day on August 5.
On August 14 Ms Patterson released a statement to "clear up the record" regarding her innocence.
Simon Patterson, son of two victims and estranged husband of Ms Patterson, spoke at a memorial for his family on August 31.
The investigations remain ongoing, police said.
Anyone with information is urged to contact Crime Stoppers on 1800 333 000 or to report confidentially log onto www.crimestoppersvic.com.au
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