'Anna boiled to death in bath with her boyfriend - cruel police theory doesn't add up'

The family of a woman who tragically died in a scalding bathtub alongside her boyfriend have shared their dark fears over her mysterious death.

Ana Carolina Silva, 41, a nail salon owner, and military officer Jeferson Luiz Sagaz, 37, and were found dead inside a motel room in Sao Jose, Brazil, on August 11.

The couple had spent the day celebrating their four-year-old daughter's birthday at a food park, before later partying at a nightclub. They dropped their child off at Jeferson's sister's house and then checked into their accommodation, the Dallas Motel, shortly after midnight. They were said to have last been seen around 11:30pm, according to local reports.

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Family members raised the alarm when the duo didn't arrive to pick up their little girl the next day and police soon made a harrowing discovery. The couple were found dead - with no signs of injury - in their motel room bathtub. The water temperature had reached 50C, while a space heater was also set to high, according to police.

A toxicology report found traces of cocaine and very high blood alcohol levels for both Jeferson and Ana. Investigators, who also analysed CCTV footage and the couple's car, say they passed out in the bath filled with scorching water.

"The cause of both deaths was exogenous poisoning, favouring the process of heatstroke with intense dehydration, thermal collapse, culminating in organ failure and death," Chief Medical Examiner Andressa Boer Fronza said.

The report states that the substances combined with alcohol and extreme heat increased their risk. A total of 16 forensic tests, carried out by the Civil Police, ruled out possible causes of death including electric shock, drowning, carbon monoxide poisoning or foul play.

But Ana's family have since expressed fears that the mum may have been forced to take drugs and are demanding 'justice'. In a passionate statement released to the media, they said unequivocally that she was "not a drug user" and that they had "concerns of possible forced ingestion or poisoning".

"It is with deep indignation that we, the family of Ana Carolina de Silva … repudiate the fake news that has been spread," the statement says. "Although reports indicate the presence of substances in her blood, we affirm with complete certainty that Ana was not a drug user.

"Given the inconsistencies, we raise serious concerns about possible forced ingestion or poisoning and demand a rigorous, transparent and impartial investigation." The heartbroken family said they wish to "preserve Ana's memory and dignity, [and to] ensure that the truth prevails over cruel and unjust speculation".

In response to the police concluding the case, the family added: "We will not allow her story to be tarnished by unjust assumptions. We will continue to seek answers, confident that justice will be served."

In a press conference, chief inspector Felipe Simao said the couple "had a busy social life but did not have a drug habit". "The big issue raised in the statements we took, talking to people involved in this, is that they did not have the habit of using cocaine," he noted. Police also said there was no known history of violence.

"It may be that the physical constitution, both his and hers, were not compatible with the use of a substance like that, especially when combined with alcohol," said Chief Simao added.

Jefferson and Ana Carolina had been together for almost 20 years and were described by friends as devoted parents and sociable. The couple's orphaned daughter is now understood to be in the care of relatives after her birthday celebrations turned into a complete tragedy.