By Justin Sink
Despite his resignation, Miller will appear Friday before the House Ways and Means Committee, where more details of the response to the scandal will likely be revealed.
House Speaker John Boehner (R-Ohio) has called for the criminal prosecution of those involved.
"My question isn’t about who’s going to resign, my question is, who’s going to jail over this scandal?” Boehner said at a Capitol press conference on Wednesday.
“There are laws in place to prevent this type of abuse,” Boehner added. “Someone made a conscious decision to harass and hold up these requests for tax-exempt status. I think we need to know who they are and whether they violated the law. Clearly someone violated the law.”
Attorney General Eric Holder said earlier this week he was launching a probe into the targeting.
President Obama called the conduct of the IRS employees "inexcusable" in a statement Wednesday night.
"Americans have a right to be angry about it, and I'm angry about it," Obama said.
Bloomberg News reported Thursday that the White House plans to announce a new acting IRS commissioner this week, although the nomination of a permanent leader will take more time.