Arsenic has been found in the blood of one of three women who died after eating birthday cake in a suspected poisoning in Brazil, a police chief told local media.
The highly toxic substance was also identified in the blood test results of a 10-year-old boy and the woman who made the cake, both of whom remain in hospital.
Five members of the same family fell ill after eating the cake at a gathering in Torres, in the southern state of Rio Grande do Sul, on Monday afternoon.
Police sent the cake for testing, and said several expired food items were also found during a search of the woman's home. They added that it is not yet clear whether the suspected poisoning was intentional.
The results of the cake test are expected to be available by next week, according to local media.
On Friday, police requested the exhumation of the body of a man, the husband of the woman who made the cake, from his grave. He died in September of food poisoning, but police said his death was presumed natural at the time.
She is not considered a suspect in either case at this time, and investigations are ongoing.
Six out of seven people at the birthday party ate cake on Monday afternoon, including the woman who baked it.
Police told Brazilian television stations that she was the only one believed to have eaten two slices of her homemade cake, and her test showed the highest levels of arsenic.
Speaking to local media, Police Chief Marcos Vinicius Veloso said some family members complained that the cake tasted “peppery.”
The family then began experiencing symptoms such as vomiting and diarrhea, and five of them sought medical help at Nossa Senhora dos Navegantes Hospital at around 01:00 local time (04:00 GMT) on Tuesday.
The hospital said that hours later, two sisters died of cardiac arrest. Local media reported that they were Maeda Bernice Flores da Silva, 58 years old, and Tatiana Diniz Silva dos Santos, 43 years old.
The third victim, whose blood tests showed traces of arsenic, died later Tuesday evening from shock after food poisoning, the hospital said.
She has been named locally as 65-year-old Newa Diniz Silva dos Anjos.
Arsenic is a naturally occurring mineral element.
Its inorganic form is highly toxic and is classified by the European Union as a Class 1 carcinogen – meaning it is known to cause cancer in humans.
According to the World Health Organization, people are exposed to high levels of inorganic arsenic through drinking contaminated water or using it in food preparation, as well as irrigating crops, industrial processes, and smoking tobacco.
Because arsenic is found in soil, small amounts can get into food, although these levels are generally so low that they are not a cause for concern.
It is also used, albeit in limited cases, in pesticides and pharmaceuticals.
