Former Fifa vice president Jack Warner has made a televised address in Trinidad, saying he will prove a link between football's governing body and his nation's elections in 2010.
"I will no longer keep secrets for them who actively seek to destroy the country," Warner said.
Warner also said in the address, which was a paid political advertisement, that "I reasonably actually fear for my life".
Still, a half-hour after the speech aired, Warner appeared at his Independent Liberal Party's rally held under a canopy on a residential street.
At least a couple hundred people were present when Warner spoke, many of them having not seen the televised remarks.
Warner said he has documents and cheques that link Fifa officials, including embattled president Sepp Blatter, to the 2010 election in Trinidad and Tobago.
"I apologise for not disclosing my knowledge of these events before," Warner said.
At his rally, a half-hour into his remarks, Warner - mopping sweat from his forehead several times - told supporters that he will not hold back in his new-found plan to expose scandal.
He said he has compiled reams of documents and is delivering them to his lawyers, for them to disseminate as they see.
"Not even death will stop the avalanche that is coming," Warner said as his supporters cheered in celebration. "The die is cast. There can be no turning back. Let the chips fall where they fall."
Warner also said that when he heard Mr Blatter was stepping down, he wrote him to urge his immediate departure from Fifa.
"Blatter knows why he fell. And if anyone else knows, I do," Warner said.