Former FIFA official Jack Warner accused the soccer body and its departing president, Sepp Blatter, of influencing his native Trinidad and Tobago’s election in 2010, saying that he was prepared to release reams of evidence of corruption at FIFA.

Mr. Warner, who is one of 14 people named in a U.S. indictment accusing them of complicity in widespread fraud in world soccer, said in a televised address in Trinidad on Wednesday that he feared for his life after compiling a series of documents that he alleged prove links between...