José Hawilla, the Brazilian businessman whose testimony helped investigators arrest and indict numerous officials in the FIFA corruption scandal, has died at the age of 74.
Hawilla owned and founded sports marketing company Traffic Group, one of the companies at the centre of the widespread corruption within world football.
He was arrested in 2013 on charges of paying high-ranking officials bribes to secure marketing rights for major tournaments and matches in South America for Traffic.
Hawilla was then indicted the following year and pleaded guilty to wire fraud, racketeering, money laundering and obstruction of justice.
The Brazilian avoided a lengthy prison sentence after agreeing to co-operate with investigators as part of a plea bargain.
He forfeited around $151 million (£113 million/€130 million) in money illegally obtained through bribes and kickbacks.
His testimony was considered crucial for prosecutors in their corruption investigation and led to the indictments of several officials from FIFA and the South American Football Confederation.
Hawilla also provided evidence during the FIFA trial in New York City in December, where former FIFA vice president Juan Angel Napout and ex-Brazilian Football Federation head Jose Maria Marin were convicted.
According to reports, Hawilla was suffering from respiratory problems at the time of his death.
The former sports journalist passed away at Sao Paulo's Sirio Libanes hospital four days after being admitted with breathing and respiratory difficulties, the reports said.
The investigation in the US has seen a total of 42 officials and entities indicted by the United States Department of Justice.
American authorities are involved as the money was allegedly channeled through the country using US banks.
The implicated officials are accused of taking millions of dollars of bribes from marketing firms in exchange for sponsorship and marketing deals for regional football tournaments and other matches.