That’s the thing IF the Republicans were serious about getting to the bottom of this they would march out enmasse and say “They are lying. There is no way this can happen. Produce the emails or be arrested.”
The GOP is not interested in truly investigating the IRS scandal. Behind closed doors Boehner and McConnell are likely cheering on the IRS in their efforts to kill the tea party. The GOPe leadership is letting the IRS take the lead in killing the tea party so they don't have to work as hard in killing it themselves.