The House’s chief investigative committee on Tuesday accused the IRS of stonewalling its probe into the agency's unfair targeting of Tea Party groups and other politically-affiliated organizations, saying Congress has received only a fraction of the documents it requested and many of those are useless.
The House Oversight and Government Affairs Committee letter directly blames acting Commissioner Danny Werfel for the “systematic manner” in which his agency has “attempted to delay, frustrate, impede and obstruct” the committee’s investigation, despite his promising just weeks earlier to fully cooperate.
“The actions of the IRS under your leadership have made clear to the committee that the agency has no intention of complying completely or promptly with the committee’s oversight efforts,” wrote committee Chairman Rep. Darrell Issa, R-Calif.
The letter also states that obstructing a congressional investigation “is a crime” and that the committee will be forced to use a “compulsory process” should the IRS continue to use its tactics.
A high-ranking committee staffer told FoxNews.com that process could include subpoenas.
"We are doing everything we can to fully cooperate with the committees, and we strongly disagree with any suggestions to the contrary," an IRS spokesman said in response to the letter. "Given that all documents must be carefully reviewed to protect taxpayer privacy, this continues to be a time and labor intensive review process."
The spokesman also said 70 IRS attorneys are working full-time reviewing documents, the agency continues to update committee staffers as the requests are being processed and that the number or related documents is closer to 460,000.
The letter by the Republican-led committee was sent as Congress tries to learn more about the targeting, including who at the agency’s Washington headquarters might have known about, led or coordinated the activity and whether it was politically motivated.
It cites at least three instances in which the IRS has failed to comply, since revelations in May that the IRS unfairly targeted the groups from 2010 through 2012 when they were applying for tax-exempt status.
The agency has turned over just 12,000 pages of the roughly 64 million pages it deemed potentially relevant to the investigation, Issa said.
Furthermore, many of the documents are duplicates and so excessively redacted that they are “completely unintelligible and useless,” according to the letter.
Additionally, Republicans on another House committee released a report Tuesday that claims conservative groups seeking tax-exempt status were more closely scrutinized by the IRS than their progressive counterparts.
Tea party and other conservative groups were, on average, asked three times as many questions as progressive groups, said the report by Republicans on the House Ways and Means Committee. Conservative groups were less likely to be approved for tax-exempt status and more likely to have their applications delayed, the report said.
The Oversight and Government Affairs Committee’s other concerns are that the IRS blocked employee Cindy Thomas -- a manager in the agency’s Exempt Organizations Determinations office -- from turning over key documents and that the agency in late July released a 30-day review to the media before giving it to the committee.
The letter was sent one day after the committee asked for an inspector general investigation into allegations the IRS also politically targeted groups that already had tax-exempt status, including the Washington-area based Leadership Institute, which trains conservatives.
The Associated Press contributed to this report