Victoria Police have arrested a 49-year-old woman at the centre of an investigation into a suspected mushroom poisoning that left three people dead.

Erin Patterson was arrested by homicide squad detectives at her home in Leongatha in South Gippsland just after 8am on Thursday.

Her Gibson Street home is being searched with assistance from Australian Federal Police detector dogs.

Police say she will be interviewed after the search and the investigation remains ongoing.

“Today’s arrest is just the next step in what has been a complex and thorough investigation by homicide squad detectives and one that is not yet over,” homicide squad Detective Inspector Dean Thomas told reporters.

Heather Wilkinson, 66, her sister Gail Patterson and brother-in-law Don Patterson, both 70, died after falling ill following a lunch at Ms Patterson’s Leongatha home in July.

Ms Wilkinson’s husband Ian, 68, spent close to two months in hospital critically ill.

“This investigation has been subject to incredibly intense level of public scrutiny and curiosity,” Det Insp Thomas said.

“It’s particularly important that we keep in mind that at the heart of this, three people have lost their lives.

“These are three people who by all accounts were much beloved in their communities and are greatly missed by their loved ones.”

Police cars were seen parked outside Ms Patterson’s home on Tuesday morning as half a dozen specialist officers and trained dogs inspected the property.

A garage and shed were searched while the canines went in and out of the house.

Police believe the symptoms the four diners experienced are consistent with being poisoned by death cap mushrooms.

Homicide detectives previously named the Pattersons’ daughter-in-law Erin Patterson as a suspect as she cooked the lunch that is believed to have led to the deaths.

She has previously been interviewed by police and was released without charge.

In a statement to police obtained by the ABC, Ms Patterson said she made a Beef Wellington using button mushrooms from a major supermarket and dried mushrooms bought at an Asian grocery store.

The 49-year-old said she ate a serving and later suffered bad stomach pains and diarrhoea, contrary to the suggestion of detectives that she did not fall ill.

She has previously denied any wrongdoing.

Victoria Police have not commented on Ms Patterson’s statement other than to say it was not one taken by officers.

By Rachael Ward in Melbourne

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