OMAHA, Neb. (AP) -- Federal prosecutors want to know more about billionaire investor Carl Icahn's efforts while he was an adviser to President Donald Trump to change the renewable fuel credits system that was costing one of his companies millions of dollars.
Icahn's company said in a filing with the Securities and Exchange Commission last week that it had received a subpoena for records related to the federal Renewable Fuels Standard and Icahn's role with the White House.
Icahn didn't immediately respond to a message Wednesday.
Icahn resigned in August just before The New Yorker published a story detailing potential conflicts and even possible criminal law violations involving refining rules.
The head of the Environmental Protection Agency has said that he never promised Icahn that changes would be made to the renewable fuel credit rules.