It may be hard to fathom, but more than 13 years after the September 11, 2001, terrorist attacks on the World Trade Center and the Pentagon, the public is still being kept in the dark about a critical issue related to the events of that dreadful day.

As former Senator Bob Graham (D-Florida), who chaired the Senate Intelligence Committee from 2001 to 2003, put it in an April 17 opinion piece in the Tampa Bay Times, “This is the essential unanswered question remaining from 9/11: While the hijackers were inside the United States, did they act alone or did others facilitate them?” Specifically, as Graham and others have noted, there is a host of evidence suggesting that senior figures from Saudi Arabia financed and assisted the atrocity that was perpetrated on American soil.

Nonetheless, Washington is adamantly refusing to share all the facts regarding Riyadh’s involvement with the American people. It is time for this to change.

We all remember that horrific autumn day when commercial airplanes were hijacked, turned into guided missiles and used to murder nearly 3,000 people, changing the world forever.

At the time, it was widely reported that 15 of the 19 hijackers were Saudis, as was Osama bin-Laden.

But there is plenty of reason to believe that the desert kingdom’s connection to 9/11 is even more sinister.

In the wake of the attacks, the US Congress established a bipartisan commission headed by Graham and Republican Senator Richard Shelby which produced what came to be known as “the 9/11 report.”

The document made for chilling reading, and provided a thorough account of the origins of the plot and its perpetrators. The report was published in book form and instantly became a national bestseller.

But a key portion of the document was kept secret and remains so to this day.

There are 28 pages which make up Part Four of the “9/11 report,” entitled “Findings, Discussion and Narrative Regarding Certain Sensitive National Security Matters,” and nearly all were redacted. The pages are blackened out, fittingly symbolizing the black hole down which certain American officials hoped to flush the information contained therein.

The Bush administration refused to countenance the publication of this section, insisting that its release would compromise US national interests.

And the Obama administration has continued that policy. And just what was in those pages that was so provocative that it had to be kept hidden from the public? By all accounts, it relates to Saudi officials and their alleged links to the attacks.

As CBS News reported on July 30, 2003, “the redacted section lays out a money trail between Saudi Arabia and supporters of al-Qaeda.”

Among others, it singles out Omar al-Bayoumi, a Saudi intelligence agent who provided financial assistance to two of the hijackers prior to the attacks. Al-Bayoumi is said to have received funds from a charitable trust run by the wife of the Saudi ambassador to the US.

In July 2011, journalists Anthony Summers and Robbyn Swan published a book, The Eleventh Day: the Full Story of 9/11 and Osama Bin-Laden, which offered still more damning evidence.

Summers and Swan cited a US official who said there had been “very direct, very specific links” between Saudi officials and some of the al-Qaida hijackers. Others have suggested that members of the Saudi royal family may have been involved.

Indeed, as The New York Times reported two months ago, lawyers representing the families of 9/11 victims, who are suing the Saudi government, disclosed that captured al-Qaida terrorist Zacarias Moussaoui had told them that members of the Saudi royal family had been major donors to the terrorist organization in the years leading up to the attacks.

Over the years, Senator Graham repeatedly tried to get the redacted material in the 9/11 report declassified and released to the general public, but both the Bush and Obama administrations have refused to do so. But Graham continues to press on, and a resolution has now been introduced in the US House of Representatives calling on President Obama to release the 28 pages.

It is time for him to do so.

For far too long, Saudi Arabia has escaped punishment for its atrocious behavior. It continues, as Graham has noted, “to promote Wahhabism, the extreme sect of Islam that promotes violence, denigrates non-Muslims as infidels and oppresses women. Saudi Arabia was the home of al-Qaeda and was instrumental in the creation of ISIS [Islamic State].”

“These,” he added, “are the poisonous fruits that have grown from our refusal to sanction the kingdom for what it did.”

The Taliban regime in Afghanistan, which provided al-Qaida with a safe haven, was removed from power, and bin-Laden, the mastermind of the attacks, was eliminated by the US military. But the other key player on 9/11 – Saudi Arabia – has yet to be held accountable.

This is morally obscene and it must not be allowed to continue.

The American people and the rest of the civilized world have a right to know exactly what role Saudi sheikhs played in the mass murder that was carried out in the streets of New York and Washington.

And the Saudis must finally be made to understand that they cannot continue to spread extremism and intolerance with impunity.

Release the 28 pages from the 9/11 report, President Obama, and let the public decide for itself if Saudi Arabia is truly worthy of being called “friend” or “foe.”

Reprinted with author’s permission from The Jerusalem Post