A accused of with a cake allegedly laced with arsenic insists she did nothing wrong.

Deise Moura, 42, remains remained in custody after allegedly murdering Maida Bernice Flores da Silva, 58, and Neuza Denize Silva Dos Anjos, 65 and Neuza's 43-year-old daughter, Tatiana Silvia Dos Santos. She also has been arrested on suspicion of the three attempted murders of other family members.

They had all eaten bits of a traditional cake reportedly baked by Moura's mother-in-law Zeli Dos Anjos, 61, days before December 25. Police in Torres, , said they found traces of the deadly poison arsenic in the deceased family members's bodies.

But Moura today issued a statement to the media, read on her behalf by her lawyer Cassyus Pontes, in which she insists "questions must be answered" amid the probe.

"Everything’s all very preliminary. There are still questions to be answered. What is the causal link between the poison and Deise? There is no explanation of how the flour ended up in Zeli's house, or where or how it was acquired," the statement added.

"These are minimal questions to indicate the authorship of the facts. Instead, all we have are the accounts of some family members and a supposed extraction of data from a mobile phone."

Officials confirmed levels of arsenic allegedly found in the flour used were so "extremely high" that they could not have been "naturally-occurring".

It is understood police are investigating an alleged 20-year-old dispute between Zeli and other members of her family, which could have been a motive. Mr Pontes added: "Deise never hid the fact that she had disagreements with her mother-in-law. She had already mentioned it to the Civil Police in a statement. I was surprised by the preventive custody request."

Zeli’s sister Maida, who was a teacher, another sibling called Neuza and Neuza’s daughter Tatiana died within hours of eating the cake late on December 23. Tatiana’s 10-year-old son Matheus, Zeli’s great nephew, was also taken into intensive care and only released from hospital last Friday. Maida’s husband Jefferson and Zeli herself, who ate two slices of cake, also needed treatment in hospital, it is believed.

Regional security minister Sandro Caron said at a press conference yesterday: “We have very strong indications that the person who has been arrested is the perpetrator. Some details cannot yet be disclosed so as not to hinder the continuity of the investigation, but we have obtained very good information pointing to the person who was arrested yesterday being the perpetrator and acting maliciously."