On Aug. 4, sisters Heather Wilkinson and Gail Patterson died in the hospital. Patterson’s 70-year-old husband Don died on Aug. 5, officials said.
Ian Wilkinson, 68, remains in critical condition at the hospital, ABC reported.
The fifth person taken to the hospital was discharged a short time later, according to Gippsland Southern Health Service.
Homicide Squad Detective Inspector Dean Thomas said the meal was prepared and served at the home of the 48-year-old daughter-in-law of one of the couples who consumed the meal, ABC reported.
“That woman and her husband are separated, however, we’ve been advised that their relationship is amicable," Thomas noted.
Detectives have searched her home and interviewed the daughter-in-law, but she has been released pending further inquiries, according to ABC.
In a press conference, Thomas said, "Because the homicide squad is investigating this matter it doesn't automatically mean that the deaths are suspicious. At this point in time, the deaths are unexplained."
The daughter-in-law is being treated as a suspect since she cooked the meal, officials said.
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Thomas said, "She hasn't presented with any symptoms, but we have to keep an open mind in relation to this, that it could be very innocent, but again we just don't know at this point."
Two children were also present during the meal, but they didn’t fall ill. Thomas believes “they may have had a different meal” than the others.
Authorities said those that fell ill displayed symptoms of eating death cap mushrooms, but that has not been confirmed yet.
Thomas said they are “presuming at this point it’s mushrooms,” ABC reported.
Investigators are working very closely with the health department and toxicologists from Austin Health, which runs the Victorian Poisons Information Centre.
In a statement from the families of the victims, they said, "As we navigate this challenging time, we kindly request that the privacy of our family, church, and friends be respected. We need space to grieve both privately and as a community.”
The Department of Health said its investigations were ongoing.
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