In the public report of Congress' investigation of the 9/11 attacks, something strange happens after page 395. The words disappear, replaced by blank lines that go on for most of 28 pages.

It's the part of the report that discusses evidence of foreign support for the terrorists, specifically Saudi Arabia. For more than 12 years, those pages have remained sealed by order of President George W. Bush and then President Obama.

The administrations stood their ground, despite pleas from Congress members of both parties, families of 9/11 victims and many others to declassify the report. The mystery of the 28 pages has become one of the hottest secrecy battles in Washington.

The debate was inflamed earlier this year when the man known as the "20th hijacker" claimed that members of the Saudi royal family bankrolled Al-Qaida. Zacarias Moussaoui is serving a life sentence in federal prison after his arrest in Minnesota in August 2001. A living reminder of the government's intelligence failures before the worst terror attack in its history, Moussaoui stoked the issue by giving a sworn statement to lawyers representing 9/11 families suing Saudi Arabia. In the statement, he said he brought letters from Osama bin Laden to members of the royal family in that country.

In February, Saudi Arabia rejected Moussaoui's contentions as the lies of a "deranged criminal," and said the kingdom was cleared of culpability in a later report by the 9/11 Commission. Still, even the Saudi ambassador once complained about the redacted 28 pages. "We can deal with questions in public, but we cannot respond to blank pages," he said in 2003.

Former Sen. Bob Graham, D-Fla., who co-chaired the Senate Intelligence Committee, has continually demanded that the full report be released. U.S. Rep. Walter Jones,R-N.C., and Rep. Stephen Lynch,D-Mass., introduced a bill last year to urge the president to declassify the 28 pages.

On the House floor in February, Jones cited the Moussaoui statement and called for his colleagues to support his bill. He said he had read the 28 pages, that they pose no risk to national security.

So why do they remain off-limits? University of Virginia history professor Philip Zelikow, who was the executive director of the 9/11 Commission, said it's a matter of preventing the release of unverified information that could potentially defame innocent people. The 9/11 Commission fully investigated what was written in those 28 pages and made its findings public, Zelikow said in an e-mail.

The classification results from the secrecy "almost always" granted to grand jury and investigative data, he said. "In other words, the material is not being kept secret because of Saudi sensitivities. It is being withheld because these were law enforcement leads that had not yet been investigated."

Terry Strada suspects those 28 pages hold far more than that, so she has tried for years to make them public. On Sept. 11, 2001, Strada lost her husband Tom, who was on the 104th floor of the World Trade Center's north tower. Strada, of New Vernon, N.J., since has become a leader in a group called 9/11 Families United for Justice against Terrorism.

Last June, her group wrote a letter to President Obama — their third — entreating him to declassify the report. "After years of wars and ongoing gaping holes in the existing account of 9/11, access to the narrative-changing facts ripped from the official account is both necessary and deserved," the letter said.

The group has not received a response, Strada said.

My inquiry to the White House yielded this statement from Ned Price, assistant press secretary and director for strategic communications for the National Security Council.

"This Administration, in response to a Congressional request [last year], asked the intelligence community to conduct a classification review of this material," Price said. "We did so in keeping with the standard procedure for determining whether classified information can be publicly released. That process is ongoing."

Based on statements from Congress members who have read those pages, Strada thinks she knows what they will say: "It's going to tell the relationships that were between Saudi officials and people that were here helping the hijackers."

Whether the 28 pages bring clarity to what happened on 9/11, or muddy it further, remains to be seen. Given the interest in the events of that day, however, Americans should no longer have to fill in the blanks.