Five people sit down for a family meal – a week later three are dead

A fourth guest is fighting for his life and needs a liver transplant

But within a week, three of the guests she hosted at her home in Leongatha, a small town in Victoria's Gippsland region, were dead. The fourth remains in hospital fighting for his life.

The 48-year-old cooked for Gail and Don Patterson, and Gail's sister and her husband, Heather and Ian Wilkinson, on July 29.

All four were much-loved members of the nearby town of Korumburra, some 13 minutes drive away, where Ian is the local Baptist church pastor, the BBC reported.

Hours after the meal, the guests went to the local hospital, for what was then thought to be severe gastro, but were soon transferred to a hospital in Melbourne, 136km away.

Heather, 66, and Gail, 70, died Friday. Don, 70, on Saturday. Ian, 68, remains in a critical condition awaiting a liver transplant.

Police say the guests ate death cap mushrooms - which are highly lethal if ingested.

Erin and her two children are fine. While the youngsters are said to have eaten a different meal, police said both have been taken into state case as a "precaution" in a case that has gripped Australia and now the internet.

It is not clear if Erin, who is separated from her husband - the Patterson's son, in what has been said as an "amicable" break - ate the same food as her guests, or even if the mushrooms were served at the meal at all.

But, "nefarious activity" has not been ruled out, police told reporters on Monday.

The homicide squad's Dean Thomas said: "At this point in time, the deaths are unexplained.

"It could be very innocent, but we just don't know."

Erin, who cooked the lunch, has reportedly said she had no idea what happened and that she would never hurt her family.

A BBC report quoted her as saying she "can't fathom what has happened".

Approached by reporters outside her home, Erin declined to answer questions about the meal she served, but professed her innocence: "I didn't do anything; I loved them."

She is also grieving, and labelled Gail, her ex-husband's late mother, "the mum I didn't have" and aid her children had lost her grandmother.

"They were some of the best people I've ever known… I'm devastated they are gone."

Related links:

Jonnie Irwin marks emotional ‘last ever’ milestone with his young son

‘Cha Cha Slide’ creator DJ Casper has died aged 58

Sandra Bullock’s partner Bryan Randall has died aged 57