U.S. Sen. Tammy Duckworth, D-Ill., is urging the FBI to investigate whether financier Carl Icahn violated federal anti-corruption laws in his former position as a special advisor to President Donald Trump. In a letter Wednesday to FBI Director Christopher Wray, Duckworth contended Icahn apparently engaged in a conflict of interest by pushing for a change in the Federal Renewable Fuel Standard program that would benefit his own financial interests.