An Army Delta Force commando who infiltrated Benghazi to rescue U.S. diplomats, spies and security officers during a 2012 terrorist attack “was critical to the success of saving numerous lives,” according to a citation awarding him the military’s second-highest honor.

Delta Force’s role was not disclosed in any public report or congressional testimony. The Army citation for the Distinguished Service Cross, posted on a website for Army personnel, provides the first detailed look at what one of the commandos, Master Sgt. David R. Halbruner, accomplished.