The woman accused of killing three of her relatives and attempting to kill three others with a poison-laced Christmas cake reportedly searched online for information about arsenic prior to the crime.

Deise Moura, who is the daughter-in-law of one of the victims who survived the poisoning incident, was apprehended at her residence in Rio Grande do Sul on suspicion of triple homicide and attempted murder.

The Christmas cake, made by her mother-in-law Zeli Dos Anjos, resulted in the deaths of three family members during a holiday gathering in Torres on December 23.

Brazilian judicial officials confirmed to TV station RBS TV that an initial analysis of Deise Moura’s phone showed ‘Internet searches, including on Google Shopping, for the word arsenic and other similar ones.’

The suspect, the daughter-in-law of Zeli dos Anjos who baked the cake, is said to have carried out the searches in November as well as days before the victims died or fell ill.

Brazilian media reports pointed to the evidence on Deise’s mobile phone being a key part of the case against her.

Earlier today officials confirmed the source of the poisoning had been arsenic-laced flour in the cake that was eaten.

They said the toxic chemical was present in ‘extremely high concentrations’ which were far too high to be naturally occurring and were enough to be fatal.

Mother-of-one Zeli is still in hospital fighting for her life, while her two sisters Maida da Silva, 58, and Neuza Dos Anjos, 65, both died along with Neuza’s daughter Tatiana Dos Santos, 43.

They lost their lives within hours of eating the cake, with police chief Marcus Vinicius Veloso saying today that the flour found in Zeli’s home had contained large amounts of arsenic. 

‘We suspect the individual arrested entered Zeli’s house and then contaminated the flour,’ the investigating officer revealed at a press conference today. 

Police and forensic officers confirmed that ‘elevated levels’ of arsenic had been found in the cake and in the blood and urine of those who had died, as well as those who survived.

Veloso added that other substances were found in searches of the suspect’s home at Nova Santa Rita, but he said tests and investigations were still ongoing and he could not comment further.

Police said that the ‘disagreements’ between the suspect and Zeli stretched back almost 20 years, but they refused to go into what exactly they were other than to say ‘further elements would be released in due course’. 

When asked what the family circumstances were, Veloso said: ‘We knew there had been minor disagreements between the suspect and elements of the family for several years.

‘On the face of it all those at the party were close and harmonious but when we extended our investigations we found motives that were probably behind this poisoning.

Police have also confirmed that they plan to exhume the body of Zeli’s husband Paulo, who died last September from ‘food poisoning’ to establish whether there were traces of arsenic in his body.

Veloso added: ‘We have the evidence, very strong and robust evidence that it was her behind this crime, and we have the reasons, but we cannot go into details yet.’

According to Marguet Mittman, director of the General Institute of Expertise (IGP), the source of the contamination was the flour used to make the cake consumed by the victims.

She told the press conference: ‘Very high concentrations of arsenic were identified in the three victims. So high that they are toxic and lethal.

‘To give you an idea, 35 micrograms are enough to cause death. In one of the victims, there was a concentration 350 times higher.’

She added that 89 samples were collected from the home of the woman who made the cake and only sample, of flour, showed high arsenic concentrations.

Brazil’s Ministry of Justice confirmed to MailOnline today that an arrest warrant had been issued for Deise ‘on suspicion of committing triple homicide, with a futile motive and using poison, and three attempted homicides, with a double aggravation.’

The ministry’s statement added that ‘the suspect will have a custody hearing on Monday afternoon.’

Police are said to have first begun investigating Deise after an apparent argument with a relative at the victims’ funeral last month.

Deise is said to have placed a ‘set of rosary beads and a rose’ in the hands of Maida and Tatiana as they lay at the cemetery in their caskets, a gesture which prompted an extraordinary outburst from one furious relative who a source told MailOnline shouted: ‘Why are you here? You didn’t like any of them. Everyone knows.’

The source added: ‘Diego and Deise kept themselves apart from the rest of the family the last few months. They didn’t really participate much. There was tension.’

Tatiana’s 10-year-old son Matheus, Zeli’s great nephew, was treated in hospital and only released on Friday, while Maida’s husband Jefferson was also treated but Neuza’s husband Joao did not eat any cake and was unaffected.

Police are set to expand on what they believe lies behind the horror poisoning, with reports in Brazil pointing to the suspect and Zeli having fought in the past in a dispute said to be linked to what subsequently occurred. 

It comes after MailOnline revealed that Zeli’s first husband Paulo Luis, 68, died after eating a banana that had been contaminated, with officials set to exhume his body from its final resting place next Thursday as part of their probe.

It was at Zeli’s seaside property that she made the cake on December 23, which she took to Maida’s apartment for the party, and at the house police have seized ingredients including dried fruit and flour, as well as pesticides.

Last week police said they are ‘not aware of any disputes within the family’ but are keeping an open mind while waiting for results from lab tests which are due back any day and provisional reports revealed arsenic in the blood of the victims.

Investigative sources confirmed Paulo’s body would be exhumed next Thursday for further analysis as none were taken after doctors at Torres hospital ruled he had died from food poisoning.

Family members have told MailOnline that he and Zeli suddenly fell ill after eating some mashed bananas they had grown from a plant in their garden, and which may have been contaminated after floods swept through the region in May.

A the time Zeli was also taken to hospital but recovered while Paulo died within hours of being admitted.

The group of seven at the Christmas party complained the cake she baked tasted ‘bitter and peppery’ within minutes all were vomiting and a fleet of ambulances was called to take them to hospital.

Maida, a retired teacher, was the first to die on Christmas Eve, Neuza passed away a few hours later, followed by her daughter Tatiana. 

Zeli’s ten-year-old great nephew Matheus, Tatiana’s son, was also taken ill and spent a week in intensive care before being moved to a paediatric unit on Friday night from the Senhora dos Navegantes hospital in Torres.

Paulo’s brother Joao – married to Neuza – did not eat any cake but Maida’s husband Jefferson had a few mouthfuls and was also taken ill but did not require a stay in hospital.

Just days ago, Jefferson’s sister Isabel Moraes, 54, exclusively told MailOnline that she thought someone with a ‘grudge’ had been responsible for targeting the family describing the tragedy as ‘strange’.

When contacted by MailOnline to ask for her reaction to the arrest she said: ‘The whole family is shocked. We just don’t know what to say, someone who is so close to us, we never imagined it.’