As CIA Director Michael Hayden prepares for a closed-door meeting on Capitol Hill with intelligence committee lawmakers, White House lawyers are telling the press shop to keep a tight lip against questions about destroyed CIA videotapes.

The Justice Department and CIA inspector general are conducting a joint preliminary inquiry into the 2005 destruction of videotaped interrogations of two terror suspects to determine whether a full probe is needed. While the investigation is under way, attorneys say they want White House spokeswoman Dana Perino to stop commenting.

"I think that that's appropriate, and I'll adhere to it," Perino said Monday, piqued by a White House press corps question on whether the advice was meant to build a "wall of silence" around the investigation.

"I can see where that cynicism that usually drifts from this room could come up in this regard. What I can tell you is I try my best to get you as much information as I can," she said.

The tapes contained the interrogations of two high-value detainees, including Abu Zubaydah, an Al Qaeda operative whose confessions helped lead the U.S. to Khalid Sheik Mohammed, the man named responsible for the planning of the Sept. 11, 2001, terror attacks, and accomplice Ramzi Binalshibh.

Another tape recorded the interrogation of Abd al-Rahim al-Nashiri, the man behind the bombing of the USS Cole in Yemen in 2000. Both tapes are said to have shown waterboarding, or simulated drowning, during the questioning.

Hayden is set to appear on Tuesday before the Senate Select Committee on Intelligence, on Wednesday for a briefing with House intelligence panelists and on Thursday for a general briefing for all senators with Director of National Intelligence Mike McConnell.

In anticipation of his appearance, Intelligence Committee Chairman Silvestre Reyes and Ranking Republican Pete Hoekstra said they were launching an investigation whether CIA followed the appropriate protocol in alerting Congress of its plan.

"Director Hayden's note to the workforce on Dec. 6, 2007, implied that our committee had been properly notified about the destruction of certain videos in 2005. Based on our review of the record, this does not appear to be true. Our investigation will review issues surrounding the destruction of videos, the CIAs failure to notify Congress of this important matter, and related questions concerning the CIAs interrogation program," Reyes and Hoekstra said in a written statement.

The director's appearances are among many question-and-answer sessions taking place throughout Washington as to why the tapes would have been destroyed, even against the advice of then-White House counsel Harriet Miers.

"You know, you can speculate. Were there things on those tapes that they didn't want to have seen, that didn't conform to what the attorney general would allow them to do? Were they just trying to bury the general subject?" Intelligence Committee Chairman John D. Rockefeller, D-W.Va., said Sunday on CBS' "Face the Nation."

"I mean, the whole idea of taping — I don't have anything against taping because it works out for the benefit of the one who is being interrogated because any, you know, bad treatment clearly comes up on that. And then it also protects the person who is doing the interrogating by showing that he or she is doing it in the proper fashion. But these particular tapes, I don't know why they were destroyed," Rockefeller said.

Hayden said Thursday that the tapes were destroyed out of fear they would be leaked and reveal the identities of the interrogators. But defense attorneys for one terror suspect Mahmoad Abdah, a Yemeni national, are suggesting the destruction violated a June 10, 2005, court order to "preserve and maintain all evidence and information regarding the torture, mistreatment and abuse of detainees."

Meanwhile, Sen. Joe Biden, chairman of the Senate Foreign Relations Committee and a 2008 Democratic presidential candidate, said Sunday he doesn't trust Attorney General Michael Mukasey to conduct the inquiry.

"He's the same guy who couldn't decide whether or not waterboarding was torture and he's going to be doing this investigation," said Biden, who voted against Mukasey's confirmation earlier this fall.

Biden said Sunday that appointing a special counsel will allow the investigation to be "taken out of the political realm."

"It appears as though there may be an obstruction of justice charge here, tampering with evidence, and destroying evidence. And this is — I think this is one case where it really does call for a special counsel. I think this leads right into the White House. There may be a legal and rational explanation, but I don't see any on the face of it," he said.

On Monday, he repeated his call. "I wish that this White House had enough integrity to police themselves but they have shown that they do not," Biden said.

But Rockefeller said he thinks his committee can properly investigate the matter.

"I don't think there's a need for a special counsel, and I don't think there's a need for a special commission," he said. "It is the job of the intelligence committees to do that."

Sen Chuck Hagel, R-Neb., a frequent war critic, said he too is curious about the White House connection.

"It's hard for me to believe that senior members of the White House somehow didn't pay attention to this or didn't know about it. And you have a counsel in Harriet Miers or whoever it might be over there not telling somebody about it," said Hagel, who appeared with Rockefeller.

"I mean, maybe that was what happened. Maybe they're so incompetent that that's what happened. But I would say that is gross malfeasance and incompetency if in fact that did happen," Hagel said.

At the very least, say Hoekstra, R-Mich., and Jane Harman, D-Calif., the CIA failed to fulfill its obligation to keep Congress informed of its activities.

"The only way Congress can have faith in the intelligence we receive is for the administration and intelligence community to follow the law by keeping the congressional intelligence committees "fully and currently" informed on intelligence matters. The controversy over the recording and destruction of interrogation tapes by the Central Intelligence Agency underscores this point, and the negative consequences when they don't," Harman and Hoekstra wrote in an editorial that appeared in Monday's Wall Street Journal.

Perino said the White House stands by Hayden's ability to conduct the inquiry, and is preserving documents that may help the case.

"We are in a fact-gathering stage and we are providing them information," she said.

A couple of Republican presidential candidates have also argued it's a good idea to look into the decision behind the tapes' destruction.

"When we start destroying documents, what are we destroying them for? Are we doing it for security purposes or to cover somebody's rear end? If we're covering somebody's rear end, we need to expose their rear end and kick their rear end for doing something that's against the best interest of the United States and the responsibility and the respectability of this country," said Mike Huckabee.

Arizona Sen. John McCain, also a candidate, said he too thinks the case should be investigated.

"The actions, I think, were absolutely wrong. I'm glad that the attorney general is going to investigate it. ... What this does in a larger sense is it harms the credibility and the moral standing of America in the world again. There will be skepticism and cynicism all over the world about how we treat prisoners and whether we practice torture or not," McCain said.

Both GOP presidential candidates appeared on "FOX News Sunday With Chris Wallace."

FOX News' Molly Henneberg contributed to this report.