The Justice Department investigation into whether Sandy Berger (search) copied and stole terrorism documents from the National Archives is focused on one highly classified report about the Clinton administration's response to a plot to bomb Los Angeles International Airport, FOX News has learned.

Sources familiar with the investigation said that Berger, Clinton's former national security adviser, took numerous copies and drafts of that report, and other related documents.

The report may be of interest to investigators because of handwritten margin notes on some of the copies, which may be attributable to Berger, sources said. Since the documents themselves have not been released, the specifics of those notes were not immediately clear.

However, a government official said the investigation will likely lead to the declassification of the report.

The terror scheme in question is the millennium bomb plot (search), which was planned for Jan. 1, 2000.

Algerian national Ahmed Ressam (search) was convicted in April 2001 of terrorist conspiracy and eight other charges related to the plot. He was arrested in Port Angeles, Wash., in December 1999 after crossing the Canada-U.S. border with a car allegedly with bomb-making material. Authorities said Ressam, 33, had ties to Usama bin Laden (search).

Seattle's millennial celebrations, and those in several other cities, were canceled as a result of Ressam's arrest.

Prosecutors say statements from Ressam prompted the government to seek the July 2001 arrest of Abu Doha (search), described as a London Al Qaeda operative. Doha has been charged with conspiring with Ressam to blow up Los Angeles International, but also is accused in other terrorist plots around the world.

Ressam's testimony also helped convict Mokhtar Haouari, 32, of supplying fake identification and cash for the millennium bomb plot. Haouari was sentenced to 24 years in prison.

The documents in the Berger case originated with the White House National Security Council and dealt with actions and recommendations stemming from the threat in 1999 of a terrorist attack during the 2000 millennium celebrations. The documents, written by former National Security Council aide and counterterrorism adviser Richard Clarke (search), were classified at the extremely sensitive "codeword" level, which is above the classification level for the nation's nuclear secrets.

Berger is being investigated after witnesses at the National Archives said they saw him copying notes from the copied documents, and stuffing some of the copies in his shirt and socks.

Berger was reviewing the materials in 2003 to help determine which Clinton administration documents to provide to the independent commission probing the Sept. 11, 2001, terror attacks. Berger claims he made "an honest mistake" but was innocent of any wrongdoing, saying he must have discarded the missing documents.

The House Government Reform Committee said this week that it will look into the allegations.

"At best, we're looking at tremendously irresponsible handling of highly classified information," said committee Chairman Tom Davis, R-Va.

House Speaker Dennis Hastert, R-Ill., said the questions the committee should answer include whether there was any attempt to cover up embarrassing materials, what happened to documents removed by Berger that are still missing and what security risk the entire episode poses.

The White House acknowledged that its lawyers were notified months ago about the Berger investigation. The chairman of the Democratic National Committee filed a Freedom of Information request for any correspondence about the probe between the Justice Department and the White House.

Meanwhile, the Sept. 11 commission said it was able to get all the information it needed despite the Berger snafu.

Panel Chairman Thomas Kean told reporters Friday that he and Vice Chairman Lee Hamilton were told by Bush administration officials about six months ago that Berger was the subject of a the Justice investigation.

Kean said the commission has been assured that they were able to obtain copies of each document that was apparently lost. If those lost documents had written notations on them from Clinton or others, they would have been included in those copies, Kean said.

Berger stepped down as an informal foreign policy adviser to Democratic presidential candidate John Kerry after the investigation hit the headlines earlier this week. Democrats accused the Bush administration of leaking the news for political gain and to distract attention from the Thursday release of the Sept. 11 commission report. Administration officials have denied those claims.

FOX News' Anna Stolley and The Associated Press contributed to this report.