WASHINGTON - Representative Darrell Issa on Thursday told Attorney General Eric Holder that he was “not a good witness’’ as the two clashed once again about the botched gun trafficking case known as Operation Fast and Furious.

In a hearing before the House Judiciary Committee, Issa, a California Republican, chastised Holder for failing to directly answer a question about whether the Justice Department had gathered and indexed all the materials asked for in a subpoena he issued last fall. Issa has threatened to cite Holder with contempt.