Less than an hour after the Twin Towers in New York were hit by two hijacked passenger planes, American Airlines flight 77 was directed straight into the Pentagon defense headquarters outside Washington.
66 people on board were killed and 125 people in the Pentagon.
The five terrorists who hijacked the plane that flew into the Pentagon were Saudis and it is mainly two of them, Khalid al Mihdar and Nawaf al Hamzi, who are now well documented by the FBI.
It was Mihdar and Hamzi who hung out with the man who later moved to Sweden and who, according to relatives of the dead, can sit on important information.
The kingdom has denied any involvement.
First think about suing
Stephanie Ross Desimone was pregnant when her husband Patrick Dunn was killed.
In the lawsuit, she states that Saudi Arabia has provided extensive support to al-Qaeda for a long time and that the Saudis were aware that al-Qaeda used the support to carry out terrorist attacks against the United States.
In an FBI investigation, three people are identified as being linked to the Saudi intelligence service, one of whom worked at the Saudi embassy in Washington.
When the name of the latter was published by mistake by the FBI, the US administration, which is concerned about its strong relations with the kingdom, was accused of keeping parts of the investigation secret.
"This shows that the administration has completely obscured the Saudi intervention," said Brett Eagleson, son of one of those killed in the 9/11 attacks and a spokesman for the relatives.
SVT's correspondent meets Brett Eagleson at home in his home in Connecticut.
He is convinced that the Yemeni citizen who now lives in Sweden and who was friends with two of the terrorists can contribute important information.
- He helped Mihdar and Hamzi when they were going to rent an apartment by being the guarantor of the contract, he helped them learn English, he drove them to the mosque, he helped arrange so that they could take flying lessons.
He can tell about the connection between him, the terrorists and the Saudi government, says Brett Eagleson.
The Saudis called to testify
Until the autumn of 2020, it was impossible for investigators to hear several Saudi officials at the embassy when the kingdom asserted their right to diplomatic immunity.
But then a federal judge in New York ruled that immunity could be revoked and instructed Saudi Arabia to hand over some twenty people, including several members of the royal family, to testify under oath.
- We have now had the opportunity to search higher up in the Saudi hierarchy.
"Now we can start unraveling the entire Saudi plan where they collaborated to carry out massacres," James Kraindler, one of the lawyers representing the families of the victims, told US media.
It is uncertain whether the Saudis will be heard and therefore the testimony of the Yemeni citizen is of extra importance, says Eagleson
- After 20 years, we can now find out what happened in this whole story and the person in Sweden has many answers, says Brett Eagleson