Wednesday 3 June 2015 17:15, UK
Outgoing FIFA president Sepp Blatter is being investigated by US authorities probing the corruption scandal, according to reports.
Blatter shocked the football world on Tuesday night by announcing his resignation just days after being re-elected for a fifth term as the head of world football's governing body.
Sources familiar with the probe have told US broadcaster ABC News that Blatter is being investigated by FBI and US prosecutors.
In addition, several US officials speaking on condition of anonymity told the New York Times they are hoping to build a case against Blatter by earning the cooperation of some of the officials who have already been indicted over alleged bribes totalling more than $150m (£98m).
FBI sources have also told Reuters that they are also investigating how FIFA awarded the 2018 World Cup to Russia and the 2022 competition to Qatar,
When contacted by Sky, FIFA refused to comment on the reports coming out of the United States, as did the US Justice Department and FBI.
As part of the US investigation, seven FIFA officials were arrested in Zurich, Switzerland, last Wednesday, sparking the worst crisis in the organisation's history.
A source told ABC: "Now that people are going to want to save themselves, there's probably a race to see who will flip on (Blatter) first."
The Swiss authorities have said Blatter is not a part of their enquiries, and the 79-year-old has always denied any wrongdoing.
The news of Blatter's departure came at a hastily arranged news conference in which he announced he would leave within months and called for a new election to appoint his successor.
Although the members of FIFA gave me a new mandate, this mandate does not seem to be supported by everyone in the world
Blatter said: "FIFA needs profound restructuring. I decided to stand again to be elected because I was convinced it was the best option for football.
"Although the members of FIFA gave me a new mandate, this mandate does not seem to be supported by everyone in the world."
One official said the election of a replacement might not take place until at least December.
In the interim period, Blatter promised to "focus on driving far-reaching, fundamental reforms that transcend our previous efforts".
Sponsors who raised concerns over the allegations responded positively to Blatter's resignation, as did his critics, who had called on him to go before Friday's presidential vote.
The investigation closed in on Blatter on Tuesday, when FIFA denied that his right-hand man, Secretary General Jerome Valcke, was implicated in a $10m payment relating to the 2010 World Cup in South Africa.
The South African Football Association has dismissed the allegations as "baseless and untested", and officials are holding a news conference this morning.
As speculation continues on who may replace Blatter, UEFA's executive committee is preparing to meet to discuss the crisis ahead of European football's showpiece match - the Champions League final in Berlin on Saturday.
Michel Platini, the head of European football's governing body, has been mentioned as a possible FIFA president.
Meanwhile, the testimony of Chuck Blazer is also expected to be released on Wednesday. The former FIFA executive, nicknamed "Mr 10%", reportedly helped investigators after being approached by authorities over large unpaid tax bills.
A US judge has approved the release of the transcript from the 2013 hearing in which Blazer pleaded guilty to corruption charges.
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