Rep. Jason Chaffetz is seeking charges for a former State Department employee who helped Hillary Clinton set up her private email server.

Chaffetz, R-Utah, the chairman of the House Committee on Oversight and Government Reform, sent a letter to Attorney General Jeff Sessions asking to convene a grand jury or charge Bryan Pagliano, The Associated Press reported.

Pagliano refused to answer questions from a congressional panel investigating the attacks on the U.S. diplomatic compound in Benghazi, Libya, which uncovered Clinton’s use of a private email server while secretary of State.

Chaffetz said in his letter that allowing Pagliano’s conduct “would gravely harm Congress’ ability to conduct oversight.”

Rep. Elijah E. Cummings, the ranking Democrat on the committee, slammed Chaffetz for pursuing the Clinton email case, which contributed to her losing the presidential election, instead of investigating possible conflicts of interest of President Donald Trump.

“Apparently, Chairman Chaffetz and President Trump are the only two people in Washington today who think we should still be investigating Secretary Clinton,” he said.