"Senior Republican officials, who spoke on the condition of anonymity because they were discussing confidential conversations, said that Mr. Boehner had long been suspicious of the administration’s handling of the attacks and that Mrs. Clinton’s emails gave him a way to keep the issue alive and to cause political problems for her campaign. But he thought that the task was too delicate to entrust to others and that it should remain with Mr. Gowdy, the former prosecutor.

Late last month, preserving the investigation’s credibility became more difficult when Representative Kevin McCarthy, the House majority leader, inadvertently offered corroboration of Democrats’ suspicions."