The authorities in Brazil launched an investigation after three women died and several others were hospitalized after a family ate Christmas cake laced with arsenic, police said local media.

The three women – who local media said were aged 43, 58 and 65 – died after eating cake at a family gathering on December 23 in Torres, a small coastal town in southern Brazil.

The woman who baked the cake, along with a 10-year-old child who also ate the cake, remain in hospital and are being treated for poisoning.

Civil police sent the cake for testing and said laboratory tests also showed arsenic levels in blood samples taken from the three victims.

Police said they also found several expired food items during a search of the woman’s home, CBS News partner BBC reported. The police add that it is not yet clear whether the poisoning was intentional.

Cake tests are expected next week.

News website G1 reported that police are waiting until the hospitalized woman’s condition improves to question her. In the meantime, the statements of 15 other people were taken as part of the investigation.

So far, no charges have been filed and the police have not said whether it is a case of murder.

Reports say the woman who made the cake got on well with other family members and there were no early signs of a fight.

The BBC, citing Brazilian media, said police chief Marcos Vinicius Veloso said some family members had complained that the cake had a “peppery” taste.

Pictures provided by police and posted online show a partially served dried fruit cake with white marzipan frosting and maraschino cherries on top. At the family gathering, only one person did not eat the cake and did not hit it.

According to local media, the police requested the exhumation of the body of the deceased husband of the woman who made the cake. He died in September from food poisoning, and the police considered his death to be natural at the time, the BBC reported.

Very low levels inorganic and organic arsenic are found in many food products, according to the National Institutes of Health. Testing is routine, as slightly elevated levels of either form can cause symptoms such as vomiting, abdominal pain, diarrhea, numbness and muscle cramps.

Inorganic arsenic is more toxic to humans than the natural mineral form of arsenic, and the health effects of exposure are more severe, according to the US Food and Drug Administration. The Environmental Protection Agency has designated inorganic arsenic as a carcinogen, i.e. a substance that causes cancer.