Christina Vazquez of El Pais reports an investigation has been opened to determine the cause of death of a 46-year-old woman, who became ill after eating at a one-star Michelin restaurant called RiFF in Valencia.

A total of 23 other patrons, including the victim’s husband and 12-year-old son, also fell sick after the meal but their symptoms were mild and they have reportedly all recovered. The restaurant will be closed to the public until the cause of death has been established.

Everything appears to be normal and now analytical tests will be carried out on the food products

The case was confirmed by regional health chief Ana Barceló, who expressed her condolences to the family and said that an investigation was already underway.

Barceló added that at this point she could not confirm whether the sickness had been caused by morel mushrooms that were on the restaurant’s menu. “We will have to wait for the autopsy to be carried out on the woman before we can determine whether it was the ingestion of a food that directly caused her death, or whether it prompted a state that led to this fatal outcome, or if she had an exisiting condition,” she explained on Wednesday.

Forensic teams are working to determine whether she could have been poisoned by something she ate, or whether she may have choked on her own vomit.

In a statement, the owner of RiFF, Bernd H. Knöller, announced that the restaurant will remain closed until the cause of the food poisoning outbreak is determined and “activities can resume with full assurances for the staff and the patrons.”