Fifa has said that Julio Grondona, the former finance chief of the organisation and a long-time ally of president Sepp Blatter, was the person who authorised a $10m payment that is at the heart of the bribery scandal.
Grondona, from Argentina, died last year aged 82 having been a Fifa executive member for 26 years, many of them as chairman of the finance committee. Blatter described him as "a lifelong friend" after his death.
A US justice department indictment of 18 people charged last week over football-related corruption says in 2008 a 10million US dollar bribe was paid to former Fifa members Jack Warner and Chuck Blazer from Fifa's Swiss bank account to an American account controlled by Warner.
The New York Times has reported that federal authorities believe it was Fifa secretary general Jerome Valcke who caused the payment to be made. He has denied that to the newspaper and Fifa say it was Grondona who authorised the payments.
Fifa's head of media Delia Fischer told Press Association Sport via email: "USD 10m was authorised by the then chairman of the Finance Committee and executed in accordance with the Organisation Regulations. Payments of this level require the approval of the Fifa Finance Committee."
It is not known whether Blatter would also have had to sign off such a large sum.
The US indictment says the bribe was in return for Warner and Blazer voting for the 2010 World Cup to be played in South Africa.
The indictment states: "On January 2, 2008, January 31, 2008 and March 7, 2008, a high-ranking Fifa official caused payments of USD 616,000, USD 1,600,000, and USD 7,784,000 - totalling USD 10 million - to be wired from a Fifaaccount in Switzerland to a Bank of America correspondent account in New York, New York, for credit to accounts held in the names of CFU and CONCACAF, but controlled by the defendant Jack Warner."