Some of the world’s largest broadcasters, including Fox Sports, were involved in bribe payments to Fifa officials in order to secure the broadcast rights to major South American football tournaments, a key witness in the investigation into corruption at football’s governing body has told a federal court in New York City.

Alejandro Burzaco, the former CEO of Torneos y Competencias, a major sports marketing company based in Argentina, testified that five other companies he had partnered with, including Brazilian network Globo and the Mexican network Grupo Televisa, had bribed Fifa officials during his tenure.

Burzaco gave evidence on the second day of the trial of three former South American football administrators, charged with accepting millions of dollars in bribes. The hearing is part of a sprawling federal investigation into endemic corruption at Fifa resulting in more than 40 criminal charges filed against football and marketing executives implicated in the global conspiracy.

Burzaco has already pleaded guilty to racketeering, wire fraud and money laundering conspiracies after he was indicted in 2015, and has since been assisting US authorities. He is one of 23 people to have pleaded guilty already.

The court heard how Burzaco had paid regular bribes, often six-figure sums, primarily to six senior officials of the South American football governing body, Conmebol, in exchange for the broadcast rights to the Copa Libertadores, South America’s premier international club competition.

Prosecutors homed in on the activities of T&T, a sports marketing company that has, since 2002, been jointly owned by Torneos y Competencias and Fox Pan American Sports and held the rights to the tournament.

The court was presented with a series of contracts between Conmebol and T&T, relating to the extension of broadcast rights for the tournament in 2008. Burzaco told the court he had paid senior officials, including the Argentinian football executive and former senior Fifa vice-president Julio Grondona and the former Conmebol president Nicolás Leoz, a range of “special bribes” ranging between $500,000 to $1m to secure the extension. The money was in addition to annual bribes, between $300,000 to $1.3m, that the six senior Conmebol officials were already receiving from T&T for the rights to the tournament.

T&T, Burzaco said, had created a sham company to pay out the one-off cash sums. The court saw a contract between T&T and an entity named Somerton for $3.7m.

“It’s not a real contract, sir,” Burzaco conceded as he told the court all the money had gone to pay off the officials. Burzaco noted one of the contract’s signatories was the former Fox Pan American Sports chief operating officer James Ganley. Burzaco had earlier told the court that Fox had become the majority owner of T&T in 2005.

On Tuesday evening, Fox responded to the allegations in court. “Any suggestion that Fox Sports knew of or approved of any bribes is emphatically false,” read a statement. “Fox Sports had no operational control of the entity which Burzaco ran. The entity run by Burzaco was a subsidiary of Fox Pan American Sports, which in 2008, at the time of the contract in question, was majority owned by a private equity firm and under their operational and management control.”

Earlier in the day, Burzaco had also said he had paid bribes to the three former football executives on trial.

José María Marín, the 85-year-old former head of Brazil’s football federation, Juan Ángel Napout, the 59-year-old Paraguayan who was president of Conmebol, and Manuel Burga, the 60-year-old former president of the Peruvian football federation, have denied multiple counts of racketeering, wire fraud and money laundering.