A bribe allegedly paid to Senegal's ex-athletics boss Lamine Diack supposedly secured Rio de Janeiro four votes in their successful bid for the 2016 Summer Olympic and Paralympic Games, according to the reported testimony of a key witness.
Brazilian newspaper Folha de S.Paolo reported that testimony in a plea bargain agreement by Carlos Emanuel Miranda, a former partner of ex-Rio State Governor Sérgio Cabral involved in the alleged scheme, that payments were made to "African leaders connected to the athletics sector".
Miranda's disclosure, which was made in the plea bargain in April 2017, marks the first time that the number of officials allegedly influenced has been named.
The Federal Public Prosecutor's Office in Brazil is in the process of investigating payments of at least $2 million (£1.5 million/€1.7 million) supposedly distributed to Diack from Brazilian businessman Arthur Cesar de Menezes Soares Filho in 2009 shortly before the International Olympic Committee (IOC) Session in Copenhagen where Rio de Janeiro was awarded the Games.
The Brazilian city beat Madrid by 66 votes to 32 in the third round of a contest also featuring Tokyo and Chicago.
Former Rio 2016 and Brazilian Olympic Committee President Carlos Nuzman was arrested last year in connection with the payments.
He was charged in October by the Federal Public Prosecutor's Office with corruption, tax evasion, money laundering and running a criminal organisation.
Nuzman and Cabral, sentenced for 87 years for various corruption offences, each deny wrongdoing.
"Recently, in prison, Sérgio Cabral told the collaborator [Miranda] that Arthur [César de Meneses Soares Filho], in fact, made payments to African leaders connected to the athletics sector to buy four votes, if I'm not mistaken," states Miranda in the transcript of his deposition, reported by Folha de S.Paolo.
Lawyer João Francisco Neto, a member of Nuzman's defence team, has already described Miranda's statement as "worthless".
On September 23 in 2009, nine days prior to the final IOC vote, Soares - nicknamed King Arthur - is alleged to have tried to transfer the suspected $2 million from an account held by his British Virgin Islands-based holding company Matlock Capital Group to a Société Générale account in France.
The Société Générale account was controlled by Senegal's Papa Massata Diack, the son of Lamine Diack, President of the International Association of Athletics Federations (IAAF) between 1999 and 2015.
Lamine Diack was a voting member of the IOC at the time Rio de Janeiro was awarded the Olympic and Paralympic Games.
It has also been reported by Folha de S.Paolo that an email sent by Papa Diack to Leonardo Gryner, the Rio 2016 general director who was put under investigation at the same time as Nuzman last year, suggests that there were other beneficiaries of the payment.
Diack reportedly said in an email that a delay of a portion of the payment caused "all kinds of embarrassment of people who have trusted in our commitment in Copenhagen".
Namibia's former sprinter Frankie Fredericks, also an IOC member at the time of the vote, is currently attempting to clear himself of allegations that he too received financial incentives to vote for Rio 2016.
Documents provided by American tax authorities showed that Papa Diack transferred $300,000 (£227,000/€255,000) to a Seychelles-based offshore company linked to Fredericks called Yemli Limited in 2009, through a firm linked to him called Pamodzi Consulting.
Although Rio ultimately won by 34 votes, a four-vote swing could have been key in ensuring they remained in the contest in the earlier rounds.
They received 26 votes in round one in comparison with 28 for Madrid, 22 for Tokyo and 18 for Chicago.
A four-vote swing from last-placed Chicago to Rio could have avoided a possible three-way tie for fourth position.
Papa Diack is also linked to vote-buying and secret lobbying investigations surrounding the successful Pyeongchang 2018 and Tokyo 2020 Olympic bids.
He denies all wrongdoing.
In a separate development, it has also been announced that football superstar Pelé will be called to give evidence via video-link as a defence witness for Nuzman by Judge Marcelo Bretas on May 29.
Pelé, a key ambassador for Rio who appeared in Copenhagen and in other places on the campaign trial, had been due to file a statement next week but has delayed it, according to O'Globo, on health grounds.
He has not been accused of any involvement in the scheme.
The IOC claim to be assisting Brazilian authorities with their investigation.