The death of Laudisio Curti has now added diplomatic pressure to the mix.
His uncle Joao Eduardo Laudisio has been a senior financial executive in large Brazilian groups and is general director and country head of Pall do Brasil, part of the US-based industrial multinational Pall Corporation. The family are also understood to have powerful political and business associations.
Australian media reported that the family were financing a private investigation.
An official at the Brazilian consulate in Sydney told news.com that the extremely wealthy and well-connected family would not let matters rest: "They own corporations, financial companies and are involved in the stockmarket."
Yesterday Brazil's Foreign Relations Ministry said it deplored Laudisio Curti's death and had instructed its officials in Australia to seek an official explanation.
It said the ministry had faith that Australian authorities "will conduct the investigation with due diligence".
The death is being investigated by Sydney homicide detectives and the Professional Standards Command, and will be overseen by New South Wales Ombudsman Bruce Barbour, who said the case was of significant public interest, requiring more careful scrutiny than most.
Barbour has separately been reviewing the use of Tasers by the NSW police, especially guidelines limiting the weapons to situations in which lives are at risk.
Premier Barry O'Farrell said that the investigation would be thorough, independent of government interference and transparent.
"I say to any country and to the citizens of any country, Australian law is rigorous, Australian law is independent of government interference and Australian law, 99.99 per cent of the time, gets it absolutely right," he said.
Laudisio Curti had been living in Sydney with his sister and had been studying English at a Bondi language school. Both his parents are dead.
Joao Eduardo Laudisio said his nephew had been for a thorough health check before leaving for Australia and had no medical conditions that could have increased the effects of a Taser or pepper spray. Friends in Brazil have organised a protest outside the Australian consulate in Sao Paulo.