Former CIA Director David Petraeus was interviewed Wednesday by the House panel probing the 2012 Benghazi attacks, the first of several high-level witnesses set to appear before the committee in the new year.

Petraeus spent four hours behind closed doors Wednesday answering questions from the GOP-led panel investigating the twin 2012 assaults in Libya that killed four Americans, including U.S. Ambassador Chris Stevens.

"What he is saying is completely consistent with what he's said in the past and indeed with the conclusions of the bipartisan (House) Intelligence committee report," said Rep. Adam Schiff, D-Calif., a member of both committees, as he emerged from the closed-door session.

Schiff said there was no stand-down order or gun-running.

The report, issued in November 2014, debunked persistent allegations, and found there was no intelligence failure, no delay in sending a CIA rescue team, no missed opportunity for a military rescue, and no evidence the CIA was covertly shipping arms from Libya to Syria.

Schiff said he hoped "this is the last time we have to bring the director back to repeat his testimony." But Rep. Trey Gowdy, R-S.C., the panel's chairman, said he expects to call Petraeus to testify again because several committee members did not question the retired Army general.

"We're actually not through with him," Gowdy said.

Some members of Congress have accused Petraeus of providing inconsistent stories on who and what was to blame, originally pointing to a demonstration over an anti-Islam film -- but later saying he knew the attack was terrorism from the start.

Fox News also has learned that the CIA is withholding certain Benghazi documents from the committee.

The committee's search for answers surrounding the attack has gone on for 19 months. The panel is scheduled to question former Defense Secretary Leon Panetta on Friday.

The committee said it has gone through 100,000 pages of documents and spoken with 64 witnesses so far, including 53 who had never been interviewed by a congressional committee. The attack killed four Americans, including U.S. Ambassador Chris Stevens.

The committee hopes to release a report "within the next few months," spokesman Matt Wolking said.

"The American people and the families of the victims deserve to know the truth about what happened before, during and after the 2012 Benghazi terrorist attacks, and we must do everything we can to prevent similar tragedies from happening in the future," Wolking said.

The 12-member committee has spent more than $5 million since its creation in May 2014.

Democrats say the inquiry has gone on longer than the 9/11 Commission took to investigate the terrorist attacks that killed nearly 3,000 people on Sept. 11, 2001.

Rep. Elijah Cummings, D-Md, called the Benghazi investigation "hyperpartisan and ineffective."

Instead of following the bipartisan model set by the 9/11 Commission, Cummings said Gowdy and other Republicans "continue to drag out this political charade closer to the 2016 presidential election, and the American taxpayers continue to pay the price."

Cummings and other Democrats say the committee has long since lost its focus on Benghazi and become a vehicle for Republicans to attack Hillary Clinton, the Democratic front-runner for president. Clinton was secretary of state during the Benghazi attacks.

Republicans say the committee has been hindered by stonewalling by the State Department and other executive branch agencies.

"While we are still waiting to receive crucial documents from the State Department and the CIA, and still waiting for important witnesses to be made available, the committee is diligently working to complete its thorough, fact-centered investigation," Wolking said.

Fox News' Catherine Herridge and The Associated Press contributed to this report.