The chief of the criminal division in the U.S. Attorney's Office in Arizona has cited his Fifth Amendment rights against self-incrimination in refusing on Friday to testify before the House Oversight and Government Reform Committee in its ongoing investigation into the failed “Fast and Furious” gunrunning operation. Rep. Darrell Issa, California Republican and committee chairman, said the prosecutor, Patrick J. Cunningham, had been subpoenaed by the committee to testify on Tuesday but his attorney notified the panel that Mr. Cunningham intended to exercise his right not to incriminate himself at his scheduled deposition. “The assertion of the Fifth Amendment by...