former fbi agent who worked on the 911 investigation says two saudi hijackers had help in the united states

A former FBI agent who worked on an investigation into the 9/11 attacks says two of the hijackers likely had help in the US.

Danny Gonzalez was involved in the still-classified FBI investigation 'Operation Encore,' which looked into two of the hijackers living in San Diego before the attacks, and whether they had help.

He says he believes the attackers had relied on a US-based support network.

The revelation comes on the heels of an executive order signed Friday by President Joe Biden, directing the Department of Justice to declassify some documents related to the attacks at the behest of families and survivors affected by the tragedy on the eve of its 20th anniversary. 

The families are suing the Kingdom of Saudi Arabia for what they believe was the country's official involvement in the attacks, and say the documents could provide evidence in the suit. 

The kingdom has denied it had anything to do with the attacks. Fifteen of the 19 September 11 hijackers were Saudi citizens. 

Some of the records flagged for release include those pertaining to 'Encore.'  

Former FBI agent Danny Gonzalez says two of the 9/11 hijackers he had helped investigate likely had help in the US from a support network of Saudi citizens. The pair were the subject of an investigation called 'Operation Encore.'

Nawaf al-Hazmi (left,) and Khalid al-Mihdhar were the 9/11 hijackers living in San Diego in the leadup to the attacks, and were investigated by the FBI after the attacks as part of 'Operation Encore.'

'19 hijackers cannot commit 3,000 mass murders by themselves,' Gonzalez told CBS News. 

'Operation Encore' investigated Saudis Nawaf al-Hazmi and Khlaid al-Mihdhar, who moved to San Diego in January 2001. They were two of the five hijackers who flew planes into the Pentagon. 

Gonzales says he believes the pair were helped by a US-based network of Saudis, including Omar al-Bayoumi. 

Bayoumi was working for the Saudi government when he said he randomly ran into the two at a restaurant in LA, and helped them move to San Diego, where he aided them in finding an apartment and opening a bank account. 

Al-Hazmi and al-Mihdhar also started flight school nearby. 

Bayoumi was the subject of a previous FBI investigation which had been closed at that point.

The two were among the five hijackers who helped fly planes into the Pentagon on September 11

President Joe Biden signed an executive order Friday that ordered a review of the classified documents related to the 9/11 terror attacks. Some of the documents pertain to 'Operation Encore' 

He had been noted in the 9/11 Commission Report, as an 'unlikely candidate for  clandestine involvement with Islamist extremists,'  which also said that there was 'no credible evidence that he believed in violent extremism or knowingly aided extremist groups.'

The report, released in 2004, found no official connection between the hijackers and the Saudi government. 

Gonzalez, however, says documents from 'Operation Encore' which began two years after the 9/11 Commission's report, would shed some light on the kind of help al-Hazmi and al-Mihdhar had while in the US.

He said he can't get into specifics, per orders from the FBI about revealing certain information related to the operation. 

The same goes for Ken Williams, also a former FBI agent, who had written a memo warning of potential terrorists taking flight lessons in Arizona before the attacks.

Former FBI agent Ken Williams, who had issued a memo warning of potential hijackers training at flight school in Arizona before the attacks says he shares Gonzalez' belief, but is unable to reveal more as per FBI orders   

al-Mihdhar (foreground in the yellow shirt) seen passing through Dulles International Airport in Virginia, shortly before ha boarded American Airlines Flight 77, which crashed into the Pentagon on September 11, 2001

'The evidence is there. I've seen it. But I can't get into specifics because of the protective order,' Williams told CBS.

'I can't sit on the sidelines when I know the truth,' Gonzalez said. 

Biden's executive order gives a timeline of up to six months for the release of the documents. 

His decision came after he had been told last month by nearly 1,800 Americans impacted by the terror attacks - including victims' family members, first responders and survivors - not to come to any of the 20th anniversary events unless he declassified documents that potentially show Saudi government links to the September 11, 2001 hijackers.

His order makes no mention of Saudi Arabia.  

'When I ran for president, I made a commitment to ensuring transparency regarding the declassification of documents on the September 11, 2001 terrorist attacks on America,' Biden said in a statement. 'As we approach the 20th anniversary of that tragic day, I am honoring that commitment.' 

The Twin Towers are seen on fire minutes after commercial airplanes were crashed into them. Some families and survivors affected by the attack are suing Saudi Arabia, saying the country had official involvement in 9/11, and are seeking more evidence that could aid them in the suit 

Biden's move could spare him the embarrassment of being snubbed by victims' family members at memorial events, which will take place next Saturday in New York, D.C. and Shanksville, Pennsylvania. 

Biden is expected to go to New York, but the White House hasn't made those plans official.    

Brett Eagleson, who lost his father Bruce in the Twin Towers attacks, and has been an advocate for the families, indicated they would stay skeptical until the documents are released.   

'We think President Biden deserves credit where credit is due. He's the first president to publicly embrace and acknowledge the 9/11 community's struggle. We are cautiously optimistic that we will get the documents we need, however our guard is still up,' Eagleson told DailyMail.com Friday by phone. 

'The Biden administration is asking that we trust that they will do the right thing. We are hopeful that come 9/11 we will see meaningful document production. If that is not the case, the families will be enraged,' Eagleson added. 

The executive order cites a specific set of documents that are to be released by the 20th anniversary of the attacks, while other documents could be released within six months.