The Justice Department has opened an investigation into federal prosecutors’ handling of a plea deal in which a wealthy, politically connected Florida financier avoided potentially severe penalties for sexually abusing teenage girls in favor of a relatively light state conviction.

The department’s Office of Professional Responsibility wrote in a letter Wednesday to U.S. Sen. Ben Sasse, R-Nebraska, that it would examine whether professional misconduct occurred in the highly publicized case of Jeffrey Epstein. The letter cited a series of recent articles by the Miami Herald that focused new attention on how the deal came about.