CANBERRA, Australia (AP) — Australian police on Thursday arrested the host of a luncheon gathering that left three guests dead from suspected mushroom poisoning and a fourth fighting for life.

Victoria state police executed a search warrant at Erin Patterson’s home at Leongatha where her former husband’s parents, Gail and Don Patterson, both aged 70, Gail Patterson’s sister Heather Wilkinson, 66, and her husband Ian Wilkinson, 68, gathered on July 29 for lunch.

All four guests were hospitalized the next day and only Ian Wilkinson survived.

Homicide detectives would interview Erin Patterson after the search of her home was completed, Victoria Police Detective Inspector Dean Thomas said.

“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,” Thomas told reporters.

Detectives had previously interviewed the 49-year-old about the fatal lunch but no charges have been laid.

She has publicly denied any wrongdoing.

Police say the symptoms the four diners had suffered were consistent with poisoning by wild Death Cap Mushrooms.

Australian Broadcasting Corp. reported that Erin Patterson had written in a statement that she had cooked a Beef Wellington steak dish for the lunch using mushrooms bought from a major supermarket chain and dried mushrooms from an Asian grocery store.

She wrote that she had also eaten the meal and later suffered stomach pains and diarrhea.

Police had previously searched her home on Aug. 5, the day the third diner died.

Ian Wilkinson, a Baptist pastor, was released from hospital in late September and police say he continues to recover.