Democrats on the House Benghazi committee say the panel's Republican chairman is ignoring statements by his own former lawyer indicating that the U.S. military acted properly on the night of the deadly 2012 attacks in Benghazi, Libya.

Democratic congressmen Elijah Cummings and Adam Smith say Republican congressman Trey Gowdy omitted the lawyer's comments when he fired back at the Defense Department for criticizing the GOP-led investigation into the attacks.

Cummings and Smith say in a letter that Gowdy's actions, coupled with delays that have pushed the 2-year-old inquiry into the heat of the 2016 presidential race, "have damaged the credibility of the Select Committee beyond repair." The Associated Press obtained a copy of the letter sent Sunday.

The letter is the latest volley in a dispute over the Benghazi investigation.