Holly Ratchford still finds it hard to believe that the man who lived in the apartment complex she managed would be accused of involvement in the 9/11 attacks.
"It's almost impossible for me to wrap my head around who he said he was, and who he really is. I still struggle with that," she tells the BBC.
The man, Omar al-Bayoumi, a Saudi in his early 40s, moved to the complex in San Diego, California, with his family in September 1999.
Ratchford, the property manager of 152 Parkwood Apartments, recalls him as a friendly and bubbly regular at her pool parties. A few months later, Bayoumi introduced her to two polite, unassuming men who would become her neighbours and, infamously, hijackers of American Airlines flight 77, which crashed into the Pentagon on 9/11.
Ratchford has been haunted by her connection to these three men for 25 years, feeling she was deceived by Bayoumi from the start.
"Whenever I had parties he would come and be a part of the activities," she recalls, adding that his family would invite her over for meals. "I enjoyed going over."
Bayoumi is now at the center of a $1 trillion lawsuit against the Kingdom of Saudi Arabia, brought by thousands of victims' families and survivors of the 9/11 attacks.
On September 11, 2001, 19 al-Qaeda members hijacked four planes. Two hit the World Trade Center in New York, one hit the Pentagon, and the fourth crashed in Pennsylvania after passengers resisted. Nearly 3,000 people were killed.
Bayoumi is alleged to have facilitated the plot by supporting the first two hijackers to arrive in the US, Nawaf al-Hazmi and Khalid al-Mihdhar, who lived at Parkwood for months before the attacks.
A federal judge in New York found a year ago that evidence created "a reasonable inference" that Bayoumi and a Saudi diplomat had been "co-ordinating with the Saudi government when providing assistance to the hijackers." Saudi Arabia denies the allegations and is appealing the ruling.
Ratchford, who saw Bayoumi interacting with the hijackers and witnessed him providing crucial support, has given a sealed declaration to the court but had never spoken publicly until now.
Finding Ratchford was difficult. After becoming unwittingly involved in the investigation, she moved to an isolated area in the western US.
She agreed to speak with the BBC, and her interview casts doubt on Bayoumi's account to authorities. It features in the BBC Radio 4 podcast, Intrigue: A 9/11 Story, and an upcoming BBC Panorama.
In early 1999, Ratchford, then 27, had found stability as the property manager of Parkwood Apartments in San Diego. She excelled at the job, which she loved not just for the pay but for the people, many of whom became friends.
Omar al-Bayoumi moved into Parkwood claiming to be a student. "I knew he was going to school. I'm not sure, other than that, what he did," Ratchford says.
Declassified FBI documents reveal Bayoumi's studies had effectively stopped in 1998, and he spent more time organizing religious activities, which he videotaped. This filming and his questions aroused suspicion.
"It was a general consensus of people in the San Diego Muslim community that Bayoumi was an operative of the Saudi intelligence service," Richard Lambert, who led the FBI's post-9/11 investigation in San Diego, tells the BBC.
Ratchford's focus was on rent payments, which Bayoumi could make. The FBI later discovered he was earning about $90,000 a year.
Bayoumi presented himself as an ordinary family man. Home videos show him playing with his family by the pool and on an excursion to Las Vegas. "I bought into everything that he told me. I really thought that's how he was," Ratchford says.
However, other videos show a different side. In summer 1999, Bayoumi filmed the US Capitol in Washington DC from various angles, noting a "plan" and providing reporter-style commentary. The 9/11 families' lawyers allege he was surveilling the building, while Saudi Arabia maintains it was a tourist video.
On February 3, 2000, Bayoumi brought two young men to Ratchford's office, saying they were from his mosque and needed a place to rent. They spoke no English, but Bayoumi handled the interaction.
"There was absolutely nothing unusual about them. They were nice, they were polite," she recalls.
They did not meet the income criteria, but they had cash. The next day, Bayoumi helped them open a bank account. Back at Ratchford's office, Bayoumi offered to co-sign their lease, becoming their guarantor.
The rental agreement shows Bayoumi's signatures, listing his Parkwood address as their current address. The two men, Nawaf al-Hazmi and Khalid al-Mihdhar, moved into apartment 150, near Bayoumi.
Ratchford saw the pair repeatedly in the following months. "I would have cookies and tea with them. It wasn't like they were just someone that came into the office and rented from us," she says.
Hazmi and Mihdhar moved out in May 2000. Sixteen months later, after the 9/11 attacks, a woman called Ratchford for a rental reference for them. The woman was a reporter, who then asked if Ratchford knew they were hijackers.
"And I went, 'What?'"
On September 14, 2001, FBI agents interviewed Ratchford. She provided Bayoumi's guarantor form, leading to an investigation into him as the potential facilitator for the hijackers.
Richard Lambert, now a consultant for the 9/11 lawsuit families, states, "as we began to identify the hijackers' associates, what became clear is that there was a network headed up by Omar al-Bayoumi."
The FBI found that Bayoumi's contacts helped Hazmi and Mihdhar obtain driver's licenses, apply to flight schools, receive wire transfers, and get dental treatment.
The FBI traced Bayoumi to Birmingham, UK, where he had moved before 9/11. He was arrested on September 21, 2001, by the Metropolitan Police's anti-terror branch.
Initially, Bayoumi denied knowing any of the hijackers, claiming he often helped people find accommodation but couldn't remember names. A day later, he recalled helping "Nawaf" and "Khalid," admitting they were the only ones he had supported to this extent.
Bayoumi claimed he met them in Los Angeles after overhearing them speak Arabic, and that they later showed up at his San Diego mosque needing housing. He said he drove them to Parkwood to see Ratchford.
He also claimed he avoided them after they moved in and left town, only to find they had moved on upon his return. This account conflicts with Ratchford's.
"I know that's what he said, and I know that's bullshit," she says.
Ratchford states that before bringing the hijackers to her office, Bayoumi had repeatedly asked her about finding an apartment for two people, wanting something near him and inexpensive.
She also contradicts Bayoumi's claim of minimal contact, stating she saw the three men together often, including one occasion for tea and cookies. "It's not like he just found them an apartment and never talked to them again," she says, adding they "were definitely friendly."
Ratchford also told the FBI that Bayoumi paid the hijackers' rent when they fell behind.
Bayoumi was held for seven days, but the US Department of Justice (DOJ) decided not to extradite him. He was released on September 28, 2001.
"I can't believe he got away," Ratchford says.
The FBI discovered that two companies linked to the Saudi Ministry of Defence were paying Bayoumi his $90,000 salary, despite him not working and incurring high expenses. His pay increased significantly after the hijackers arrived and decreased after they left the US west coast.
FBI agents also found letters to a Saudi government-linked charity with ties to al-Qaeda, and writings by Bayoumi that could be interpreted as "jihadist," suggesting anti-American sentiments. However, this did not lead to an indictment.
The DOJ declined to comment on decisions from 25 years ago.
Bayoumi left the UK for Saudi Arabia in August 2002. Two years later, the US 9/11 Commission concluded he was "obliging and gregarious" and "an unlikely candidate for clandestine involvement with Islamist extremists," despite the FBI not presenting all its gathered evidence.
The 9/11 families pursued Bayoumi through the courts, adding him to their $1tn lawsuit. After years of campaigning, tens of thousands of FBI documents were released, including Ratchford's interviews.
In August last year, the judge in the 9/11 families' case stated that the evidence did not support the conclusion that Bayoumi was "just an innocent participant." He also noted a "reasonable inference that all the apartment-related assistance he provided for the hijackers was not just acts of a good Samaritan, but rather that he was following" instructions from the Saudi government.
Saudi Arabia denies any involvement in 9/11 and claims sovereign immunity. The case is now with the US Court of Appeal.
For Holly Ratchford, the events of 9/11 and her connection to Bayoumi and the hijackers ended her sense of security. "My life, my ideals, my beliefs, everything changed so quickly. It was like a flip of a switch," she says.
"I felt so stupid. I trusted and I cared about people that did bad things. I don't ever want to be as blindsided as I was by them not being who they said they were."
Soon after 9/11, Ratchford quit her job and moved away from the city, seeking isolation to escape the feeling of being deceived. She now prefers to live in places where she can trust people.
She is still haunted by questions about what happened at Parkwood. "Part of me wonders if there's something I could have done if I was more strict," she says.
