After a more than two-year investigation, Menendez faces charges for what prosecutors believe were improper efforts by Menendez to help Salomon Melgen, a Florida-based doctor who was also a contributor to Menendez’s campaigns and his longtime friend. Menendez intervened on Melgen’s behalf in a dispute with the federal regulators over Medicare charges and in a bid by Melgen to secure a port security contract in the Dominican Republic.

Menendez, would be only the second U.S. senator to face a federal corruption indictment in the last 20 years. He has repeatedly denied any wrongdoing and suggested that any gifts he received from Melgen were part of a close, personal friendship that dates back to the early 1990s.

Federal prosecutors are also expected to unveil charges against Melgen connected to the gifts-for-favors allegations.