The Fifa ethics committee was investigating the president, Gianni Infantino, for allegedly under-declaring the money he spent on his election campaign, before he organised the removal of the committee’s chairmen and members in May.

The declaration of his election expenses was the second issue for which Infantino was under investigation; the ethics committee had also started preliminary inquiries into whether he improperly sought to influence the election in March of a new Confederation of African football president.

Fifa’s anti-corruption efforts criticised after speedy clearing of Gianni Infantino Read more

Before he emerged victorious in the February 2016 vote to become Fifa’s president, Infantino said publicly that he had been financially supported by Uefa, European football’s governing body, with €500,000 “to fund flights – mainly flights – around the world”. Senior Uefa sources have told the Guardian, however, that the total support Infantino received was approximately €1m.

The chair of the ethics committee’s investigatory chamber, Cornel Borbély, is understood to have been informed that Uefa’s full support was more than the figure Infantino had stated publicly and to have begun investigating whether the president’s declaration to Fifa’s electoral committee was correct.

Fifa’s rules require candidates for president to register with the electoral committee their expenditure on campaigns, which involve flying round the world to lobby national football associations for votes. Sources close to the electoral committee have told the Guardian that Infantino did declare only €500,000 to the committee.

He is understood to have been urged by the committee chairman, Domenico Scala, to be public about his budget from Uefa, considered a matter of fairness and transparency to other regional football confederations backing rival candidates. The only figure Infantino declared publicly was €500,000, on his campaign website and in interviews given shortly before the 26 February vote.

At Fifa’s congress in Bahrain in May, Infantino organised the removal of Borbély, who then complained that Fifa’s reforms after years of corruption scandals had been reversed and “incapacitated”. The tenures of Hans-Joachim Eckert, chair of the ethics committee’s adjudicatory chamber which decides whether to bring cases and sanctions, other ethics committee members, and the governance committee chair, Miguel Maduro, were also discontinued by the Fifa council on Infantino’s recommendation. Critics, including Maduro, argued Fifa has a “systemic problem”, failing to accept the independence of reforms required for better governance and anti-corruption.

Infantino was promoted in December 2015 as the chosen candidate by Uefa, where he was the secretary general, after Fifa’s ethics committee had banned the then president, Sepp Blatter, and his favoured successor, the then Uefa president Michel Platini, for malpractice. Infantino said he flew three times around the world during his campaign, which he began in October 2015 as a provisional candidate when Platini was initially suspended. Infantino also staged campaign events, including a glitzy presentation of his manifesto at Wembley, accompanied by José Mourinho and former football playing greats.

Asked then how he had funded that presentation and all his campaign expenditure, seeking a majority of votes from African and other football associations worldwide, Infantino said: “I have been very open and transparent about that. Uefa has given me a budget of €500,000 to fund flights – mainly flights – around the world. I have communicated this information to Fifa’s electoral committee and on my website as well.”

Borbély and Eckert were given no notice that their chairmanships were not to be renewed after their four-year terms were concluded, and said afterwards they had hundreds of files whose progress would now be impeded. The ethics committee had previously investigated Infantino shortly after his election, for potential conflicts of interest over his acceptance of two flights in private jets, and his expenses. He was cleared, but was said by insiders to have been greatly upset at having been investigated.

A Fifa spokesman declined to comment on whether Infantino was under investigation for the declaration of his election expenditure when the committee chairmen were removed, saying it was “baseless speculations, unfortunately put forward for ill-intended purposes”. In a statement, Fifa said: “With regard to Gianni Infantino’s campaign, all funding and expenses have been done in full conformity with all relevant regulations and also been audited accordingly. We have, however, no information on the campaign accounts of the other candidates.”