Suspended former Fifa presidential candidate Mohamed bin Hammam begins his attempt to clear his name of bribery allegations on Friday.
Fifa's ethics committee has started a two-day hearing to rule on claims the Qatari tried to bribe Caribbean delegates to vote for him as president.
Bin Hammam pulled out of the race in the wake of the allegations and was provisionally suspended on 29 May.
He has promised to provide "convincing evidence" to prove his innocence.
"There has been a campaign waged within certain quarters," he wrote in a blog.
"Why was the Fifa ethics committee in such a hurry to suspend me before the Fifa election took place and then begin to search for evidence to find if I am guilty or not?" he added.
"Why have I not been treated in a similar way to others who, according to the Ethics Committee, received inducements?"
Bin Hammam and former Fifa vice-president Jack Warner were suspended when a leaked report revealed four Caribbean Football Union (CFU) associations were either offered money, or saw the offence occur, during a meeting in May.