Former FIFA Executive Committee member Chuck Blazer has died aged 72, according to his lawyers.
Blazer, who served as CONCACAF general secretary and U.S. Soccer Federation executive vice-president, was handed a lifetime ban by FIFA from all football-related activity in 2015.
The American had pleaded guilty to racketeering conspiracy, money laundering and tax evasion in late 2013.
As part of his plea, Blazer, who had been battling cancer up until his death, agreed to work undercover to help authorities with their investigation into corruption within FIFA.
"We are truly saddened by the passing of our client and friend, Chuck Blazer," his lawyers Eric Corngold and Mary Mulligan said in a statement given to the BBC and AFP.
"His misconduct, for which he accepted full responsibility, should not obscure Chuck's positive impact on international soccer."