Yahoo News recently reported a mistake they found in an FBI court filing. In the filing, the FBI neglected to redact mention of the name of Mussaed Ahmed al-Jarrah, a Saudi diplomat whom FBI agents had suspected of directing material support to two of the Saudi 9/11 hijackers that crashed a plane into the Pentagon, killing 125. The court filing has since been removed but Pandora’s box has already reopened.

Following the long-running 9/11 investigation is a complicated, tragic, and murky affair. Of critical importance for families of the 9/11 victims is determining the extent of Saudi government involvement or complicity in the terrorist attacks that killed their loved ones. In their quest for closure, the families of victims have worked with former FBI Special Agents who were assigned on the 9/11 cases around the time of the attacks. A long suspicion, but one that is extraordinarily difficult to prove, has been that the hijackers — who were predominantly Saudi — were linked to the Saudi government.

For years, these former agents and the victims’ families have attempted to uncover any nexus between the Saudi government and the hijackers. The FBI’s recent mistake in failing to redact mention of the Saudi diplomat’s name offers them a possible breakthrough in their quest for closure.

While families of the victims sought answers themselves, the FBI was also keen on determining any possible connection between the Saudi government and the hijackers, and probed for possible links around 2012. In this investigation, the FBI focused on two Saudi individuals they suspected of assisting the two terrorists that hijacked the American Airlines plane that crashed into the Pentagon.

The first individual, Fahad al-Thumairy, was a Saudi Islamic Affairs official and radical cleric who reportedly served as the imam of a Los Angeles mosque. The second individual, Omar al-Bayoumi, was a suspected agent of the Saudi government.

In this supposed hierarchy, the two terrorists were supported by al-Thumairy and al-Bayoumi, who, in turn, received material support from al-Jarrah, the Saudi diplomat in Washington. This was evidenced by at least one instance in January 2000, when the two hijackers flew to Los Angeles and were subsequently assisted by al-Bayoumi, who found them an apartment, lent them money, and established bank accounts for them.

Evidence uncovered by the FBI during the investigation also led them to believe that al-Thumairy and al-Bayoumi had been tasked to provide such support by a third man, possibly al-Jarrah.

This third man, al-Jarrah, was a mid-level Saudi Foreign Ministry diplomat assigned to the Saudi Embassy in D.C. His reported duties included overseeing the Ministry of Islamic Affairs employees at Saudi-funded mosques and Islamic centers in the United States. It is here that the ostensible link between al-Jarrah, al-Thumairy and al-Bayoumi is made, given the latter’s role as a radical cleric and Ministry of Islamic Affairs employee in Los Angeles.