A White House official said the statements came from information in publicly available sources -- including the Koch Industries website and testimony before the President's Economic Recovery Advisory Board. But Koch Industries thinks the statements were improper, and claimed to have identified that White House official as Austan Goolsbee.
"As the Inspector General charged with ensuring, among other things, the fair implementation of our Nation's system of tax administration, pursuant to Treasury Inspector General for Tax Administration practice, I have ordered the commencement of a review into the matters alleged," J. Russell George wrote in a letter to Grassley.
George's investigation appears to only focus on whether administration employees improperly accessed and disclosed confidential taxpayer information, which would have been a violation of section 6103 of the Internal Revenue Code. But the senators wrote in their letter that making the statements even based on publicly available information might not be proper.
"Alternatively, if the statement was based on speculation, it raises the question of whether the Administration speculating about any specific taxpayer's liability is appropriate," the senators wrote in a letter last month.
A spokesperson for the IG's office told TPMuckraker that what is at issue is whether or not any confidential taxpayer information was released. The spokesperson wouldn't say whether talking about confidential tax information that had been disclosed in other forums was in and of itself improper.
President Obama has been critical of AFP and the Supreme Court decision which allowed companies like it to obscure their funding sources.
"Right now all around this country there are groups with harmless-sounding names like Americans for Prosperity, who are running millions of dollars of ads against Democratic candidates all across the country," he said in August. "And they don't have to say who exactly the Americans for Prosperity are."
ATP President Tim Phillips said after his remarks that "the President is now making shrill, desperate attacks on Americans for Prosperity and our 1,200,000 AFP grassroots activists across the nation."