Roberto Laudisio Curti, 21, died on March 18 after police tasered him up to three times on Pitt Street in downtown Sydney.
While Mr Curti's death is being examined by the NSW coroner, his family back in the Brazilian city of Sao Paulo are asking questions of their own.
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Uncle Domingos Laudisio says he fears the investigations into Mr Curti's death are not properly transparent.
"We don't know the names of the six cops who chased him," he told ABC Television.
"We don't know the names of the cops who tasered him.
"We don't know what these cops have done in the past."
Mr Laudisio says he wants everybody involved in the investigations to demonstrate they have integrity and can be trusted.
Cousin Eduardo Laudisio said he regarded Mr Curti - who lost his parents at a young age - as a brother.
"It is really difficult, I really think it is a great tragedy in my life, my first tragedy," he said.
"And I think that I have just to keep going, but I think he didn't deserve it."
Mr Curti's soccer coach Franco Polistina hit back at reports the young man had been on a two-day alcohol or drug bender in the days leading up to his death.
He says Mr Curti played two games of soccer the afternoon of his death and showed no signs of inebriation.
