WASHINGTON – A critical report issued by the House Oversight & Government Reform Committee has dismissed the findings of a blue-ribbon panel investigating the 2012 Benghazi terrorist attack, asserting that the State Department-appointed commission didn’t properly examine key witnesses and generally failed to perform a comprehensive job.

In a 98-page report released Monday, committee staff concluded that “troubling” gaps exist in the work of the Accountability Review Board (ARB) appointed by then-Secretary of State Hillary Clinton and that the “limitations inherent in the ARB’s mandate and the weaknesses in the ARB’s methodology show that a more thorough investigation is necessary.”

“The ARB blamed systemic failures and leadership and management deficiencies within two bureaus, but downplayed the importance of decisions made at senior levels of the Department,” the report read, adding that the ARB’s decision to “cite certain officials as accountable for what happened in Benghazi appears to have been based on factors that had little or no connection to the security posture at U.S. diplomatic facilities in Libya.”

Rep. Darrell Issa (R-Calif.), the committee chairman, said the ARB “was not fully independent,” noting that it “did not exhaustively examine failures and it has led to an unacceptable lack of accountability.”

But Rep. Elijah Cummings (D-Md.), the committee’s ranking member, scorned the new report, citing it as evidence that Issa and congressional Republicans have “politicized the investigation by engaging in a systematic effort to launch unsubstantiated accusations against the Pentagon, the State Department, the president and now the ARB itself.”

The controversy centers on the Sept. 11, 2012, attack on the American diplomatic mission in Benghazi, Libya, by a heavily armed terrorist group that resulted in the deaths of Ambassador Chris Stevens and three others.

At first the Obama administration suggested the attack was the result of a spontaneous protest. Subsequent investigations by the State Department and various congressional committees instead determined it was a premeditated assault launched without warning by Islamist militants.

The White House and Foggy Bottom came under severe attack from congressional Republicans and other critics for what they consider the failure of the U.S. to dash to the aid of those under attack. In early August it was reported that the U.S. had filed criminal charges against several individuals, including militia leader Ahmed Abu Khattala, for participating in the onslaught.

On Oct. 4, 2012, Clinton appointed a five-member Accountability Review Board, co-chaired by Thomas Pickering, U.S. ambassador to the United Nations from 1989 to 1992, and Adm. Mike Mullen, former chairman of the Joint Chiefs of Staff, to examine the facts and circumstances of the attacks. The panel’s report, issued on Dec. 20, 2012, sharply criticized the State Department for failing to act on embassy requests to upgrade security in Benghazi.

But the ARB refused to point a finger at higher-ups in the administration like Clinton, blaming inaction instead on four mid-level officials who were placed on paid administrative leave only to be subsequently re-instated, although in different positions. Dissatisfied with the conclusions, Issa ordered a review of the report.

“While Ambassador Pickering and Adm. Mullen have honorably served their country, the families of victims and the American people continue to wait for more conclusive answers about how our government left our own personnel so vulnerable and alone the night of the attack,” Issa said.

The White House and the State Department cited the ARB conclusions, according to the Issa report, as “the final word on the internal failures that contributed to the tragedy in Benghazi.” But for others it said the report “overvalued certain facts, overlooked others, and failed to address systemic issues that have long plagued the State Department.”

The congressional committee charges the ARB failed to conduct a thorough investigation as a result of time constraints, maintaining that “the ARB operated under significant time pressure, completing its work and issuing a final report in just over two months.” It noted that some key witnesses only appeared to provide testimony before the board once and some, like Clinton, were not questioned at all.

As an example it cited Elizabeth Dibble, the second-most senior official in the State Department’s Bureau of Near Eastern Affairs – one of the two offices directly criticized in the final ARB report. Dibble, the committee report noted, “appeared once, as part of a group and for less than two hours.”

That limited consideration, the congressional staff held, “raises a number of questions about the thoroughness of the ARB’s review. For example, aside from her participation in the short group interview, it is still unclear what information the ARB reviewed that led to the conclusion that her role or awareness of issues related to Benghazi did not warrant further inquiry.”

The Issa report also questioned the treatment of Under Secretary of State Patrick Kennedy, who played a role in rejecting requests for enhanced security at the Benghazi mission. The ARB didn’t hold Kennedy responsible for any shortcomings and he subsequently helped select not only the members of the ARB but the staff that aided the commission.

“The haphazard decision to place the four officials cited by the ARB on paid administrative leave created the appearance that former Secretary Hillary Clinton’s decision to announce action against the individuals named in the ARB report was more of a public relations strategy than a measured response to a tragedy,” the Issa report said. “Therefore, one year after the Benghazi attacks, no one at the State Department has been fired for their role leading up to the Benghazi attacks. It appears increasingly likely the Department’s primary objective was to create the public appearance of accountability.”

The Issa report also raised questions about the degree of Clinton’s knowledge about the assault.

The House Oversight & Government Reform Committee has scheduled a hearing on the issue for Sept. 19 to give panel members an opportunity to question Pickering and Mullen about the process the ARB utilized and producing its report as well as its conclusions. Staff members who put together the report critical of the ARB also will be called to testify.

Cummings rejected the Issa conclusions, noting that the ARB “fulfilled this mission by conducting one of the most comprehensive reviews in history –interviewing more than 100 people, reviewing thousands of pages of documents and viewing hours of video.”