Rabat – Sepp Blatter took world football by surprise when he has decided Tuesday to step down from FIFA after 17 years in charge of the sport’s world governing body. The stunning decision comes only four days after the 79-year-old was re-elected as FIFA boss for a fifth consecutive term.According to media reports, one of the main reasons behind Blatter’s decision could be the alleged corruption of his secretary general, Jerome Valcke. Valcke allegedly made a $10 million transfer in 2008 to Jack Warner, former CONCACAF president and FIFA vice president, who faces corruption charges in the U.S.U.S. officials are reported to believe that the money was allegedly paid as a bribe in exchange for votes to give the 2010 World Cup to South Africa at the expense of rival bidder Morocco.A letter dated 4 March 2008 has emerged apparently linking the football organization’s secretary general to the $10 million payment.In the letter, the president of the South African Football Association addressed directly to Jerome Valcke requesting the diversion of funds.In an email to the New York Times, Valcke said he had not authorized the payment and had no power to do so. A Fifa spokeswoman said the payment was authorized by the then-finance committee chairman, Julio Grondona, who died last year.Fifa says the $10m payment went towards a legitimate “project to support the African diaspora in Caribbean countries as part of “the Diaspora Legacy Programme”.Last week, seven senior FIFA officials were arrested in Zurich. U.S. federal prosecutors brought charges against other officials accused of corruption.