There is "comprehensive, convincing and overwhelming" evidence that Mohamed Bin Hammam tried to bribe officials in his bid to replace Sepp Blatter as Fifa president, according to a report.
A secret document by Fifa's ethics committee also found evidence that Jack Warner was "an accessory to corruption".
Warner resigned on Monday as Fifa vice-president and quit all football activities.
The world governing body said it had dropped all investigations into him and that "the presumption of innocence is maintained".
But the full report of the ethics committee headed by Namibian judge Petrus Damaseb said there was "prima facie" evidence that bribes had been paid to officials to support bin Hammam's campaign for the Fifa presidency, and that Warner had facilitated this.
Sky News sports producer Richard Conway said: "Mohamed Bin Hamman continues to deny any wrongdoing and has said he will continue to try to clear his name."
Bin Hammam withdrew as a candidate against Sepp Blatter on the morning of his ethics committee hearing on May 29.
Both he and Warner have consistently denied any wrongdoing. They were suspended last month pending a full inquiry.
The 17-page ethics committee document setting out their decision was faxed to Warner last week, on June 14, and three days later he informed Fifa he was resigning.
A copy of that report has been obtained by the Press Association.
It concludes that there was "compelling" evidence that Bin Hammam and Warner arranged a special meeting of the 25 members of the Caribbean Football Union (CFU) on May 10 and 11 in Trinidad and that, with their knowledge, cash gifts were handed over.
Statements from witnesses, described as "credible and correspondent" in the report, said they were handed brown envelopes each containing $40,000.
Bin Hammam said in a statement: "There is nothing I can say more than I deny the allegations and insist that I have not done anything wrong during the special Congress at Trinidad."