The US initially acknowledged the Saudi role back in 2012, when the FBI released a memo as part of its Operation Encore investigation.
Ever since, numerous reports have pointed to a Saudi involvement, including documents released by the 9/11 Commission, officially known as the US National Commission on Terrorist Attacks Upon the United States.
Riyadh has denied involvement in the attacks, which left nearly 3,000 people dead and more than 6,000 others injured, and none of the documents directly prove the Saudi government’s entanglement.
‘An open wound’
Relatives of those killed on 9/11 or from illnesses triggered by Ground Zero toxins are running out of patience as their quest for truth persists.
One of the victims suggested in an interview with Australian Broadcasting Corporation (ABC) that the extent of Saudi Arabia’s role in the September 11, 2001 has to be finally revealed, 20 years after the tragedy.
"The legal team and the FBI, investigative agencies, can know about the details of my dad's death and thousands of other family members' deaths, but the people who it's most relevant to can't know," said Brett Eagleson, whose father Bruce was among the World Trade Center victims. "It's adding salt to an open wound for all the 9/11 family members."
The families and their lawyers not only seek to get compensation but also expect Saudi Arabia to accept responsibility and end terrorism campaigns.
"If they did all three of those things, that would be a huge victory," Andrew Maloney, one of the plaintiffs' lawyers told ABC.
While the US Justice Department has given lawyers once-secret documents, they are still under a protective order, meaning their details cannot be revealed.
The department has argued that revealing the content of the documents could put US national security in danger.
Many experts believe that the reason why Washington refuses to shed light on the Saudi role is because the 9/11 was an inside job choreographed by the Bush administration.
The US used the attacks as an excuse to launch two deadly wars on Afghanistan and Iraq respectively, whose repercussions keep harming the region to this day.