SAN DIEGO -- Federal agents are investigating the possibility that a flight bound for San Diego from Boston on Sept. 11 may have narrowly avoided tragedy because the plane was grounded for mechanical problems.

Video

Authorities Investigate San Diego Connection

But perhaps even more disconcerting is that agents agents suspect that a United Airlines flight scheduled to land in San Diego on Sept. 22 may have also been targeted, 10News reported.

Agents investigating last week's attacks on the East Coast have arrested San Antonio radiologist Al-Badr Alhazmi, 34, as a material witness. He was booked on a United Airlines flight originating in Texas and scheduled to arrive in San Diego this Saturday, according to The Houston Chronicle.

Alhazmi, whose last name is similar to that of one of the men identified as a San Diego-based terrorist, was in his final year of residency at the University of Texas Health Center. He did not show up for work on Sept. 11, the day of the attacks on the East Coast.

Details regarding the investigation into whether the San Antonio to San Diego flight was targeted for hijacking were sketchy. A confidential FBI list of possible associates of the suspected East Coast hijackers includes five people -- including Alhazmi -- who apparently had reservations on the flight, according to The Los Angeles Times.

The flight has been canceled, The Times reported earlier this week.

"We are working closely with the FBI and will not release any information related to the investigation," Jenna Ludgate of United Airlines told The Times.

The search for local associates of the terrorists involved in the Sept. 11 attacks intensified after the arrest on Sunday of a man who allegedly gave financial support to two San Diego-based terrorists.

FBI agents tracked the man through local bank records, 10News reported. The man, whose name was withheld, was arrested on Sunday night.

"(He) was an associate, friend and facilitator for the two of them," a federal official told the Union-Tribune, referring to Nawaf Alhamzi and Khalid Al-Midhar.

Alhamzi and Al-Midhar, along with another man with ties to San Diego named Hani Hanjoor, have been identified as hijackers.

Authorities said that Alhamzi, 25, Al-Midhar, 34, and Hanjoor, 29, lived for a time in Clairemont and Lemon Grove in the year leading up to Tuesday's attacks in New York and at the Pentagon.

While in San Diego County, the men apparently sought training as pilots and may have attended at least one community college, FBI Special Agent Erika Foxworth said.

Authorities said that the man arrested on Sunday is believed to be a national of a Middle Eastern country. They traced him through bank accounts other financial records.

The man was arrested somewhere in San Diego County and was being held on immigration violations while prosecutors gather evidence against him, according to 10News.

Meanwhile, in Irvine, Calif., several men with possible ties to the hijackers have been questioned by federal agents, according to 10News.

The FBI stopped the men Monday night as they were loading a moving van in front of their apartment building.

The men told their neighbors they were University of California Irvine students from Yemen.

Their apartment was searched, but they were not arrested, 10News reported.

So far, federal agents have detained 75 people for questioning on immigration violations who are suspected of being involved in the attacks.