A retired Brazilian colonel who confessed to torturing and killing detainees decades ago has died from a heart attack during a break-in at his home, according to an autopsy report that has debunked murder conspiracy theories.
Paulo Malhaes, 77, died after three men broke into his family's suburban Rio de Janeiro home on Thursday.
The death had all the ingredients of a gripping murder mystery, fuelling speculations over whether it was a simply a robbery, a revenge killing or sinister cover-up.
But the autopsy report quoted by Brazilian media on Saturday found that Malhaes had died from "pulmonary oedema and myocardial infarction", indicating a heart attack was to blame.
The paper quoted pathologist Nelson Massini as saying that the findings appeared to rule out police suspicions that Malhaes was asphyxiated.
The commissioner in charge of the case, Fabio Salvadoretti, had said on Friday that Malhaes had been found lying on the floor with a pillow over his head with marks on his face and neck, suggesting suffocation was the cause of death.
Widow Cristina Batista Malhaes said the couple and a house worker had been taken hostage by three men when they returned home, and that they were held for eight hours in separate rooms.
Two computers, jewellery, 700 Brazilian reais (HK$2,418) and three military collectible weapons were stolen during the break-in.
The retired colonel's godson, Joaquim Sarmento Souza, said the burglars had received orders to kill Malhaes.
Last month, Malhaes became the first former officer from the 1964-1985 dictatorship to openly admit carrying out torture.
Protected from prosecution under a 1979 amnesty, Malhaes outlined to Brazil's National Truth Commission a sickening catalogue of crimes that took place at a secluded location in Petropolis outside Rio known as the "House of Death".
Unrepentant, the retired army officer listed in chilling detail the methods of the men involved in one of the darkest chapters of Brazil's history.