ZURICH: In a stunning twist just days ahead of FIFA's presidential election, football's governing body said Wednesday it is investigating challenger Mohamed Bin Hammam for bribery in his campaign to unseat Sepp Blatter. FIFA summoned Asian Football Confederation leader Bin Hammam and FIFA vice president Jack Warner to an ethics hearing Sunday to face allegations of corruption in the Qatari official's presidential election bid. The allegations — leveled by Warner's longtime CONCACAF ally Chuck Blazer of the United States — will likely wreck Bin Hammam's already fading hopes of defeating Blatter in the June 1 vote by FIFA's 208 national members. “In view of the facts alleged in this report, which include bribery allegations, FIFA secretary general Jerome Valcke ... requested the FIFA ethics committee to open ethics proceedings,” the football body said in a statement. FIFA said the allegations related to Bin Hammam's meeting with 25 Caribbean football leaders on May 10-11 in Warner's native Trinidad to lobby for support. “This meeting was linked to the upcoming FIFA presidential election,” FIFA said. Blatter's campaign adviser, Brian Alexander, said the FIFA president would not comment on the case. Bin Hammam helped organize the hastily arranged meeting after he was unable to attend the CONCACAF annual congress one week earlier in Miami. The Qatari official was denied a visa to enter the US, despite traveling on a diplomatic passport. His campaign's administrative oversight left Blatter a clear run to lobby for votes in Miami. Blatter has been endorsed by confederation leaders in Africa, Europe, Oceania and South America. Warner's 35-member confederation has not yet officially backed either candidate. Bin Hammam and Warner are both scheduled to be in Zurich Thursday for a meeting of FIFA's finance committee, and to attend FIFA's executive committee meeting chaired by Blatter Monday. They face lengthy suspensions from all football duties if bribery allegations are proven. Both were reelected unopposed this year to lead their continental bodies for four more years. Two other Caribbean Football Union officials, Debbie Minguell and Jason Sylvester, are also being investigated by FIFA. The four people under suspicion have been invited to “take a position” by Friday and report to the ethics panel Sunday. Bin Hammam was a key player in Qatar's successful bid to host the 2022 World Cup. Qatar was accused in a British Parliamentary hearing of paying $1.5 million bribes to two FIFA executive committee members. On Wednesday, a whistleblower from the Qatar bid had been scheduled to submit evidence to Valcke and FIFA legal director Marco Villiger in Zurich. However, FIFA said the whistleblower “decided not to attend the meeting” based on legal advice. FIFA said Warner and Bin Hammam will face an ethics panel chaired by Namibian judge Petrus Damaseb. Charges denied Bin Hammam has denied bribery allegations and says he's confident he'll be allowed to stand against Sepp Blatter next week. The Qatari football leader says the allegations are “a tactic being used by those who have no confidence in their own ability to emerge successfully from the FIFA presidential election.” Bin Hammam says if there's “the slightest justice in the world, these allegations will vanish in the wind.”