Mr. Salame, 30, who ran FTX’s subsidiary in the Bahamas and was a prolific donor to Republican politicians, is the fourth executive in Mr. Bankman-Fried’s circle of close advisers to admit to criminal conduct since FTX collapsed in November. Three others — Nishad Singh, Caroline Ellison and Gary Wang — have already pleaded guilty to fraud charges and agreed to cooperate against Mr. Bankman-Fried. A representative for federal prosecutors said Mr. Salame was not cooperating with the investigation.