Fifa president Gianni Infantino has denied wrongdoing after leaked documents suggested he signed off on a contract with two businessmen who have since been accused of bribery.
Hugo and Mariano Jinkis bought TV rights for Uefa Champions League football and immediately sold them on for almost three times the price.
The 2006 contract was signed off by Infantino when he was a Uefa director.
Infantino says he is "dismayed" that his "integrity is being doubted".
News of the contract came to light after 11 million documents were leaked from the Panamanian law firm Mossack Fonseca.
Uefa initially denied doing business with any of the 14 people who have been indicted by the FBI in its investigation into corruption in world football.
It has now told the BBC the TV rights were sold to the highest bidder in an open and competitive tender process.
A senior Fifa source has told the BBC the deal should be examined by the governing body's ethics committee in the interests of transparency.
What is this all about?
Hugo Jinkis and his son, Mariano, are fighting extradition from Argentina to the United States.
In May 2015, US prosecutors alleged that, as the owners of Cross Trading, they paid millions of dollars in bribes to South American football officials over several years in order to gain lucrative television rights for regional football tournaments.
It is claimed the money was paid to senior football officials in exchange for cheap broadcasting rights that could then be sold on for a substantial profit.
Infantino is named on a contract with Cross Trading that concerns the Ecuadorian rights for Uefa Champions League football between 2006-7 and 2008-9.
Cross Trading, an offshore company registered to the tiny Pacific island of Niue, paid $111,000 (£78,000) for those rights.
Then, according to leaked documents, it sold them to Ecuadorian TV broadcaster Teleamazonas for $311,170 (£220,000).
Cross Trading also paid $28,000 (£20,000) for the rights to the Uefa Super Cup, selling those to Teleamazonas for $126,200 (£89,000).
There is no evidence to suggest Infantino received a bribe relating to the 2006 contract with Cross Trading, and no suggestion Teleamazonas was in any way complicit in any wrongdoing.
At the time, Infantino was the director of legal services with European football's governing body, Uefa.
Cross Trading also has links to Juan Pedro Damiani, a member of Fifa's ethics committee who has already been placed under internal investigation.