The leaders of the Administrative Review Board that investigated the attacks on US facilities in Benghazi, Libya, appeared before the House Government Reform and Oversight Committee Thursday, and offered testimony that further undermined the already-tattered credibility of their own probe.

In descriptions that emphasized their friendly, even collaborative dealings with the top State Department officials who were ostensibly among the subjects of their investigation, Ambassador Thomas Pickering and Admiral Mike Mullen defended their work and shrugged off criticism from Republicans on the panel.