CINCINNATI -- Senator Rob Portman is speaking out about the Cincinnati Internal Revenue Service's targeting of conservative groups seeking tax-exempt status.
Portman said the scandal hits particularly close to home not only because he's from Cincinnati, but because he sits on the senate finance committee, which oversees the IRS.
Thursday afternoon, Portman once again brought up the possibility of bringing in a special prosecutor to investigate what happened.
"My concern is that if the administration isn't forth coming on these answers, then a special prosecutor will be necessary, Portman said. "We have to get to the bottom of it."
Portman explained some of his frustrations Thursday and said the U.S. Senate Committee on Finance submitted 41 questions to the IRS that they wanted answered by last week.
But Portman said they're still waiting.
The finance committee held a hearing on the scandal last month.
So far there have been five congressional hearings on Capitol Hill.
Portman and Rep. Steve Chabot spoke to a large gathering of tea party activists in Cincinnati at the end of May.
"The question is, 'How high up did it go?'" Chabot said, adding: "And what's going to be done about it?"
The Obama administration has said no senior officials were involved in targeting.
Chabot said investigations are still unfolding, and it's important to follow the facts and not to overreach in drawing conclusions. Portman linked the IRS scandal to the Benghazi attack investigation, and both he and Chabot said the Obama administration must be more forthcoming.
Portman said he finds it hard to believe that a couple of "rogue agents" in Cincinnati were responsible for the conservative targeting and that it was done as an efficiency measure to handle a large number of applications, as was initially suggested.
Portman said he hoped whistle-blowers would come forward to let people know what happened.
He said the possibility of a criminal investigation should at least be used as leverage to push for answers from the Obama administration.
Otherwise, Portman said, "We're going to have to go up to the next level."