Japanese Olympic Committee (JOC) President Tsunekazu Takeda has denied knowledge of links between Singaporean company Black Tidings and Papa Massata Diack, who is at the centre of a French corruption investigation.
Takeda became embroiled in an alleged vote-buying scandal related to Tokyo's successful bid for the 2020 Olympic and Paralympic Games earlier this month.
The Japanese official, considered a well-respected and influential International Olympic Committee (IOC) member, was indicted on corruption charges in France in December.
He is suspected of authorising the payment of bribes in order to help the Japanese capital secure the hosting rights for the Games.
Takeda denies wrongdoing and claimed he was "never involved in any decision-making process" relating to payments worth $2 million (£1.5 million/€1.75 million) made to Black Tidings.
The payments were made before Tokyo was awarded the 2020 Olympics and Paralympics at the IOC Session in Buenos Aires in 2013.
The account holder has been closely tied to Papa Massata Diack, son of the disgraced former International Association of Athletics Federations (IAAF) President and IOC member Lamine Diack, currently being held in France and facing corruption charges.
According to Agence France-Presse, Takeda told investigators last month that he was unaware of any business relationship between Black Tidings owner Tan Tong Han and Papa Diack at the time of the payments.
He also claimed he had played no role in selecting the consultancy firm, alleging Black Tidings had been recommended by Dentsu.
The Japanese advertising firm are Tokyo 2020’s marketing agency, while they also oversee the IAAF’s marketing strategy.
Papa Diack was formerly the IAAF marketing consultant.
"At the time that the contracts were signed, neither the bid committee nor I knew of the existence of these links," Takeda told investigators, according to AFP.
"I did not know Papa Massata Diack, I had never had a conversation with him, I did not know who he was.
"Tan must have known a lot of people at the IAAF and supplied information to the Olympic bid committee about IOC members within the IAAF."
It has been alleged that payments made to Black Tidings were directed to the elder Diack, with authorities in France suspecting corruption or money laundering by an unknown person.
It is claimed that money was diverted to the older Diack to sway the votes of other members.
Takeda has insisted it was merely a "consultancy contract signed through appropriate approval procedures".
He also offered an apology last week at a short press conference, conceding that "that this trouble could possibly affect the Olympic Movement".
Last week, the IOC Ethics Commission confirmed a file had been opened on Takeda but stressed he retained the "presumption of innocence".
The Black Tidings account has been linked to Papa Diack, with the company embroiled in ongoing investigations by prosecutors into both the Tokyo 2020 bid and the IAAF.
Last week Papa Diack claimed had had met Takeda only twice, with the first coming at the IAAF World Championships in Berlin during 2009.
The second meeting came at the IOC Session in 2013, where he claimed he shook hands with the JOC President in their first encounter before congratulating him after the vote.
Tokyo, the winner of the first round of the vote for the 2020 Olympics and Paralympics, defeated Istanbul by 60 votes to 36 in the second ballot.
Madrid were eliminated in the first round.
"Mr. Takeda has never discussed such things with my father, never discussed anything like that with anybody that I know," Papa Diack told Kyodo.
Papa Diack, who insists the allegations are the “biggest lie in the history of world sport", remains in Senegal but is subject to a red notice issued by Intepol back in 2016.
He has blamed the accusations on a smear campaign to tarnish his father's reputation, while claims he cannot leave Senegal as he has “has been stripped of his passport.”
Last week, Black Tidings owner Tan was handed a one-week jail sentence in Singapore for lying to an official.
He was given the sentence after giving "false information" to a Corrupt Practices Investigation Bureau employee.
Black Tidings was connected to an athletics scandal which saw three officials handed life bans for blackmailing athletes to cover-up failed drugs tests.
Papa Diack, former IAAF treasurer and Soviet Union athletics coach Valentin Balakhnichev and Russian race walk trainer Alexei Melnikov were all kicked out of the sport for their role in the scheme.
All three officials denied wrongdoing but it was ruled that they had been guilty of blackmail since 2011, receiving payments including £435,000 ($634,000/€583,000) from Russian marathon runner Liliya Shobukhova.