The country’s top investigator seemed to be in the dark Thursday when pressed to provide details of the IRS investigation into the tax agency’s targeting of Tea Party and conservative groups.

Rep. Jim Jordan, R-Ohio, seemed to rattle FBI Director Robert Mueller for not knowing the specifics surrounding the IRS probe.

“You’ve had a month now to investigate,” Jordan said. “This has been the biggest story in the country and you can’t even tell me who the lead investigator is. You can’t tell me the actions the inspector general took which are not typically how investigations are done. You can’t tell me if that’s appropriate or not. This is not speculation. This is what happened.”

Mueller repeatedly declined to answer Jordan’s questions, saying he couldn’t because the investigation was ongoing or that he’d have to get back to the lawmakers with answers.