Sepp Blatter, the head of FIFA could be interviewed "within weeks" as part of a corruption investigation that engulfed football's governing body last night.
fter a day of crisis, which saw 14 football officials and executives arrested at the request of the FBI, some in Zurich, and FIFA accused of "rampant, systematic and deep-rooted" corruption, the Swiss authorities said that Mr Blatter could be questioned.
The FIFA president was given the warning by the office of the Swiss attorney general. It is conducting its own inquiry into alleged vote-rigging over the Qatar World Cup bid.
The escalation of that inquiry came as the FBI claimed it had uncovered 24 years of "brazen corruption, undisclosed illegal payments, kickbacks and bribes" by FIFA officials. The American inquiry alleges that votes for the award of the 2010 World Cup - ultimately given to South Africa - were bought with bribes.
In what was labelled the darkest day in the body's history:
FIFA was accused of running a "World Cup of fraud" by a US attorney.
The FBI said that the "beautiful game" had been "hijacked" by corruption.
Swiss authorities announced that they had opened a criminal inquiry into the 2018 and 2022 World Cup decisions.
US authorities claimed that "bribes and kickbacks" were paid in the awarding of the 2010 World Cup and the 2011 presidential election which was won by Mr Blatter.
Jack Warner, the former FIFA vice president who stepped down in 2011 following corruption allegations, was accused of receiving $10m in bribes.
The revelations came days before votes are due to be cast in the 2015 FIFA presidential election and will bolster calls for the organisation to be reformed and for the 2018 and 2022 votes, won by Russia and Qatar, to be rerun. Last night, UEFA called for the presidential election to be postponed.
Damian Collins, the British Conservative MP for Folkestone and Hythe who has campaigned against corruption in FIFA, said that there was "no question" that the 2018 and 2022 decisions should be rerun. "It's staggering that Fifa is ignoring calls for the votes to be rerun," said Mr Collins. "Several of the individuals involved in making the decision have resigned because of corruption charges and the words from the Department of Justice could not be more damning."
FIFA has faced many corruption allegations in recent years, including over the decision to award the 2022 competition to Qatar.
But the events this week will add to pressure on the president of world football's governing body. There are currently two criminal investigations into FIFA.
Yesterday, Swiss police arrested several of its officials at the five-star Baur au Lac hotel in Zurich where they had gathered in preparation for Friday's vote.
The men arrested there included Jeffrey Webb, the head of the Confederation of North, Central America and Caribbean Association Football (CONCACAF) and FIFA vice-president and Costa Rica's national football chief Eduardo Li, who was expected to join FIFA's executive committee (Exco) on Friday.
Eugenic Fugueredo, of Uruguay, the president of South American football's governing body, Conmebol, was also held by Swiss police, as was Rafael Esquivel, the president of the Venezuelan Football Federation.
They were joined by Exco member Jose Maria Marin, from Brazil, FIFA development officer Julio Rocha of Nicaragua, and the UK's Costas Takkas, an attache to the president of Concacaf.
In a statement, Mr Blatter said: "Today's action by the Swiss office of the attorney general was set in motion when we submitted a dossier to the Swiss authorities late last year. Let me be clear: such misconduct has no place in football and we will ensure that those who engage in it are put out of the game."