A judge on the U.S. Court of Appeals for the D.C. Circuit is calling for an en banc hearing to clarify the scope of protection accorded to statements made during congressional ethics investigations, according to an opinion unsealed Thursday (pdf).

Judge Brett Kavanaugh was part of a three-judge panel that ruled from the bench in favor of a congressman whose lawyers argued in January in a rare closed-door hearing that documents and testimony provided to the House Ethics Committee cannot be used against the congressman during a grand jury investigation.