The family of suspected mushroom poisoning victim Ian Wilkinson has told 9News he is "showing signs of improvement" in hospital.
It comes as Victoria's deputy police commissioner warned the investigation into the incident that killed three people would be lengthy.
Deputy Police Commissioner Wendy Steendam also confirmed that cook Erin Patterson's written letter seen and reported by the ABC and The Age was not a formal police statement.
Steendam told ABC radio that the statement being "provided to media outlets" was "unhelpful" to the police investigation.
"What I would say is that anything that's in the media … working on an investigation through the media is unhelpful to our investigation," Steendam said.
The deputy commissioner also emphasised that the statement was not a formal police statement.
Steendam further said the police investigation was being undertaken carefully and would take some time.
"It's not going to be quick," she said.
Patterson's statement revealed she was also hospitalised with bad stomach pains and diarrhoea after eating the meal, which is believed to have caused the death of her former in-laws Don and Gail Patterson, as well as Gail's sister Heather Wilkinson.
Heather's husband Ian Wilkinson is still in hospital but has improved after eating the meal at Patterson's Leongatha home on July 29.
Don, Gail and Heather all died a week after eating it.
The statement also claimed Patterson bought dried mushrooms from an Asian grocer in Mount Waverley in Melbourne months ago that were used to cook the beef wellington.
It said she also used locally bought fresh mushrooms.
Patterson was interviewed by police but released without charge. Patterson denied any wrongdoing over the meal in the statement.
"I am now wanting to clear up the record because I have become extremely stressed and overwhelmed by the deaths of my loved ones," Patterson said.
"I am hoping this statement might help in some way. I believe if people understood the background more, they would not be so quick to rush to judgement.
"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."
She also revealed her children were not at the lunch and instead went to the movies.
Patterson said the children did eat the beef wellington the following night as leftovers but she scraped the mushrooms off the dish before it was served as they don't like them.
