Singapore - Two men who launched challenges to Sepp Blatter for the leadership of world football body FIFA have been targeted in an attempted blackmail scam, a report said on Saturday.
Prince Ali bin al Hussein and Michael van Praag, who has now pulled out of the race, were both approached by Kenya-based conmen who said Blatter had gathered sensitive information about them.
Singapore's The New Paper and Dutch daily De Volkskrant said the men demanded money to hand over the information from what they claimed was a smear campaign orchestrated by Blatter.
According to The New Paper, Jordan's Prince Ali, who is now Blatter's sole challenger in next week's FIFA vote, and van Praag both confirmed approaches.
"We have had a number of individuals coming forward with similar allegations," a spokesman for Prince Ali was quoted as saying.
"Our approach has been to try and set up meetings with these individuals so we can assess them and the information they are giving for ourselves."
The conmen said the director of an India-based security company put together a surveillance report on Prince Ali for submission to Blatter's daughter, Corinne.
But when contacted by The New Paper, both the investigator and Corinne Blatter denied all knowledge and said they had been set up.
"I do not know who is behind it but it is clearly intended to damage my father's reputation," Corinne Blatter was quoted as saying.
According to the report, the approaches by email appeared genuine but details such as the investigator's phone number and email address were wrong.
"I have no idea who would want to set me up, especially on such an elaborate scam as this," the investigator, who was not named, told The New Paper.
"I have never worked for Ms Corinne Blatter in any way."
Van Praag received an email which stated: "Some time in late August 2014, Sepp commissioned some espionage work on you fearing you might stand against him in future."
The Dutch FA chief said: "What do you think it would mean for my image if I were to respond to those e-mails?
"If it is true that they are working on a case against me,then so be it. I have nothing to hide."
Van Praag and Portuguese great Luis Figo withdrew from the FIFA race on Thursday, leaving Prince Ali as the only man standing between Blatter and a fifth term as president on May 29.
Swiss-based FIFA has been hit by a succession of scandals, including claims of widespread bribery in the run-up to Qatar's successful bid to host the 2022 World Cup.