The State Department's inspector general's office has opened an investigation into the department's "independent" Benghazi review panel, the "Accountability Review Board" seeking to discover if key testimony was never sought or blocked from being delivered.

Fox News:

The IG's office is said by well-placed sources to be seeking to determine whether the Accountability Review Board, or ARB -- led by former U.N. Ambassador Thomas Pickering and former Chairman of the Joint Chiefs of Staff Adm. Mike Mullen -- failed to interview key witnesses who had asked to provide their accounts of the Benghazi attacks to the panel.

The IG's office notified the department of the "special review" on March 28, according to Doug Welty, the congressional and public affairs officer of the IG's office.

This disclosure marks a significant turn in the ongoing Benghazi case, as it calls into question the reliability of the blue-ribbon panel that then-Secretary of State Hillary Clinton convened to review the entire matter. Until the report was concluded, she and all other senior Obama administration officials regularly refused to answer questions about what happened in Benghazi.

But State Department spokesman Patrick Ventrell disputed the characterization of the review, saying it is "simply false" to assert the panel is being investigated.

"Rather, it is conducting a review of the ARB process itself going back two decades, looking at how Boards are convened, their standards, and the implementation of ARB recommendations," he said.

Since the ARB report was issued in December -- finding that "systemic failures and leadership and management deficiencies at senior levels" well below Clinton were to blame for the "inadequate" security at Benghazi -- Clinton and other top officials have routinely referred questioners to the conclusions of the board report. Now the methodology and final product of the ARB are themselves coming under the scrutiny of the department's own top auditor.

There may not have been any direct interference from the State Department into the review board's deliberations, but that's not the issue. Members of that board knew what their job was and set out to do it; absolve higher ups of responsibility. It's an old Washington game and is the purpose of many"independent" review panels.

Pickering served as Ambassador to Russia under Bill Clinton and also held the #3 post at State during the Clinton years. Mullen served as Obama's chairman of the joint chiefs for the first few years of his administration. Both men are old Washington hands and knew exactly what was expected of them. They delivered.

Hearings next week before Rep. Issa's oversight committee should give us an interesting look at what the review board missed.