The CIA did not inform the FBI when it learned that Mihdhar and Hazmi had entered the United States, and Mihdhar was not placed on any watchlists until late August 2001.

Mihdhar was placed on a CIA watchlist on August 21, 2001, and a note was sent on August 23 to the Department of State and the Immigration and Naturalization Service ( INS ) suggesting that Mihdhar and Hazmi be added to their watchlists.

Regarding the CIA's refusal to inform the FBI about Mihdhar and Hazmi, author Lawrence Wright suggests the CIA wanted to protect its turf and was concerned about giving sensitive intelligence to FBI Agent John P. O ' Neill, who Alec Station chief Michael Scheuer described as duplicitous.

Wright also speculates that the CIA may have been protecting intelligence operations overseas, and might have been eying Mihdhar and Hazmi as recruitment targets to obtain intelligence on al-Qaeda, although the CIA was not authorized to operate in the United States and might have been leaving them for Saudi intelligence to recruit.

Quso was able to identify Mihdhar, Hazmi and Attash in photos provided by the FBI, and he also knew Marwan al-Shehhi, a hijacker aboard United Airlines Flight 175.

Hazmi was one of the four names on the list that were known for certain.

A search for Hazmi and other suspected terrorists commenced, but the search was not very aggressive and they were not located until after the attacks.

Hazmi was initially dismissed as a " muscle hijacker " following the attacks, but was later revealed to have played a larger role in the operational planning than previously believed.

In addition to Hazmi and Mihdhar, two Yemenis were selected for a southeast Asia component of the plot, which was later scrapped for being too difficult to coordinate with the operations in the United States.

Saudi Intelligence was also aware that Hazmi was associated with Al-Qaeda, and associated with the 1998 African embassy bombings and attempts to smuggle arms into the kingdom in 1997.

Hazmi and Mihdhar also met with Fahd al-Quso, who was later involved in the USS Cole bombing.

Hazmi got a recommendation from the mosque for a job at a nearby Texaco station and car wash, a business whose former owner, a Muslim, was known to help young men in need of work.

On July 12, 2000, Hazmi filed for an extension of his visa, which was due to expire.

His visa was extended until January 2001, though Hazmi never filed any further requests to extend it beyond that.

At the time, Hazmi was living with Khalid al-Mihdhar, another 9 / 11 hijacker.

According to the FBI and the 9 / 11 Commission report, Hazmi first entered the United States on June 29, 2001, although there are numerous unconfirmed reports that he was living in San Antonio, Texas with fellow hijacker Satam al-Suqami much earlier.

In late 1999, Hazmi, Attash and Yemeni went to Karachi, Pakistan to see Mohammed, who instructed them on Western culture and travel ; however, Mihdhar did not go to Karachi, instead returning to Yemen.

After the meeting, Mihdhar and Hazmi traveled to Bangkok, Thailand on January 8 and left a week later on January 15 for the United States.

Neighbors thought that Mihdhar and Hazmi were odd because months passed without the men getting any furniture, and they slept on mattresses on the floor, yet they carried briefcases, were frequently on their mobile phones, and were occasionally picked up by a limousine.

Mihdhar and Hazmi took flight lessons on May 5, 2000 at the Sorbi Flying Club in San Diego, with Mihdhar flying an aircraft for 42 minutes.

Hazmi obtained a B-1 / B-2 tourist visa on April 3, 1999 from the US consulate in Jeddah, Saudi Arabia, using a new passport he acquired a few weeks earlier.

Hazmi went with the two Yemenis, Tawfiq bin Attash ( Khallad ) and Abu Bara al Yemeni, to Karachi, Pakistan where Khalid Sheikh Mohammed, the plot's coordinator, instructed him on western culture, travel, as well as taught some basic English phrases.

After the meeting, Mihdhar and Hazmi traveled to Bangkok in Thailand on January 8, and left a week later on January 15 to travel to the United States.

On May 5, Hazmi and Mihdhar took a lesson for one hour, and additional lessons on May 10 at the Sorbi Flying Club, with Hazmi flying an aircraft for 30 minutes.

At this time, Mihdhar transferred his vehicle's registration to Hazmi, and he left San Diego on June 10, 2000.

Hani Hanjour arrived in San Diego in early December 2000, joining Hazmi, but on December 10, they were seen leaving their Mount Vernon address leaving for Phoenix, Arizona where Hanjour could take refresher flight training.

On December 22, Hanjour and Hazmi signed a lease for an apartment in the Indian Springs Village complex in Mesa, Arizona, moving in on January 9.

2 days later on April 1, 2001, Oklahoma police officer C. L. Parkins pulled Hazmi over for speeding in their Corolla along with an additional citation for failing to use a seatbelt together totaling $ 138.

In late 1999, Hazmi, Attash, and Yemeni went to Karachi, Pakistan to see Mohammed, who instructed them on Western culture and travel ; however, Mihdhar did not go to Karachi, instead returning to Yemen.

In early February 2000, Mihdhar and Hazmi rented an apartment at the Parkwood Apartments complex in the Clairemont Mesa area of San Diego, and Mihdhar purchased a used 1988 Toyota Corolla.

In the beginning of February 2000, Mihdhar and Hazmi rented an apartment at the Parkwood Apartments, a 175-unit complex in the Clairemont Mesa section of San Diego, near the Balboa Drive Mosque.

* February 2000: Hazmi and Mihdhar move to San Diego.

Before leaving for Malaysia, Khalid Sheikh Mohammed doctored Hazmi's Saudi passport in order to conceal his travel to Pakistan and Afghanistan, and make it appear that Hazmi had come to Malaysia from Saudi Arabia via Dubai.

A Saudi, Hazmi had a relatively long history with al-Qaeda before being selected for the attacks.

Upon arriving in San Diego, California, Mihdhar and Hazmi were to train as pilots, but spoke English poorly and did not do well with flight lessons.

In June 2000, Mihdhar left the United States for Yemen, leaving Hazmi behind in San Diego.

Mihdhar and Hazmi were among the first group of participants selected for the operation, along with Tawfiq bin Attash and Abu Bara al Yemeni, al-Qaeda members from Yemen.

Once selected, Mihdhar and Hazmi were sent to the Mes Aynak training camp in Afghanistan.

On January 5, 2000, Mihdhar traveled to Kuala Lumpur, where he joined Hazmi, Attash and Yemeni, who were all arriving from Pakistan.

Both Mihdhar and Hazmi were secretly photographed at the meeting by Malaysian authorities, whom the CIA had asked to provide surveillance.

On January 15, 2000, Mihdhar and Hazmi arrived at Los Angeles International Airport from Bangkok and were admitted as tourists for a period of six months.

Immediately after entering the country, Mihdhar and Hazmi met Omar al-Bayoumi in an airport restaurant.

While in San Diego, witnesses told the FBI he and Hazmi had a close relationship with Anwar Al Awlaki, an imam who served as their spiritual advisor.

Mihdhar and Hazmi raised some suspicion when they offered extra money to their flight instructor, Richard Garza, if he would train them to fly jets.

Mihdhar and Hazmi moved out of the Parkwood Apartments at the end of May 2000, and Mihdhar transferred registration for the Toyota Corolla to Hazmi.

On June 10, 2000, Mihdhar left the United States and returned to Yemen to visit his wife, against the wishes of Mohammed who wanted him to remain in the United States to help Hazmi adapt.

In August 2001, Mihdhar and Hazmi made several visits to the library at William Paterson University in Wayne, New Jersey, where they used computers to look up travel information and book flights.

On August 22, Mihdhar and Hazmi tried to purchase flight tickets from the American Airlines online ticket-merchant, but had technical difficulties and gave up.