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.