Hijacking suspects quietly entered United States

By Kelli Arena
CNN Washington Bureau

WASHINGTON (CNN) -- As stories emerge about the hijackers' lives in the United States, a burning question remains: How did they get into the country and remain under law enforcement radar?

Sixteen of the 19 alleged hijackers responsible for the September 11 terrorist attacks came into the United States with legal visas. Fifteen entered on business or tourist visas and one with a visa to attend a vocational school, such as flight school.

Immigration officials say they do not have any information to suggest these men should not have been allowed in the country. "The person makes the application at a U.S. embassy in a country abroad and the State Department reviews its records to identify people who are inadmissible to the United States," said Paul Virtue, former general counsel for the U.S. Department of Immigration and Naturalization Services. "And they also have a separate database of people who are involved in terrorism that they do checks against."

VIDEO CNN's Kelli Arena looks at how suspected terrorists gained entry into the U.S. (September 20) Play video (QuickTime, Real or Windows Media)

Experts say it is not surprising the alleged hijackers were not on a watch list. Terrorist networks usually do not sacrifice high-level assets -- or members known to intelligence officials -- in suicide missions.

"They would want people that could get into the country -- preferably legally, preferably people we weren't aware of. They don't have a history with the intelligence services of law enforcement," said Ben Venzke of IntelCenter.

Once in the United States. the 19 apparently became what are known in the intelligence community as "sleeper agents" -- instructed not to draw any attention to themselves -- and to stay focused on the missions.

In this case, learning how to fly.

"They could have simply been told, 'Enter the United States, learn how to fly these types of planes,'" Venzke said. "They may not have known ultimately where this was headed or what the goal was. Then as that became necessary, they could have been in communication with other members of other cells who would have given them other directions."

At least six of the alleged hijackers attended flight schools or tried to polish their flying skills while in the United States.

Sources said one of the individuals arrested by the FBI and being held as a material witness -- Zacarias Moussauoi -- was also arrested August 17 in Minnesota on a passport violation. Sources said he came into the United States in February on a student visa with plans to attend flight school.

Moussauoi was in custody at the time of the September 11 attacks, and authorities said he was not cooperating in the investigation. According to sources, Moussauoi was studying at Airman Flight School in Norman, Oklahoma. Another person linked to bin Laden studied at the same school.

"We just do our job, like every other flight school, and train them," said Brenda Keen, admissions manager for Airman Flight School. "We are not here to do background checks on them."

Some of the alleged hijackers lived in the United States for years, renting several short-term apartments and hotels.

For the most part, all 19 maintained a low profile and avoided law enforcement suspicion, except for two -- Khalid Al-Midhar and Salem Alhamzi. The FBI received information two weeks before the terrorist attacks possibly connecting them to the bombing of the USS Cole.

A search for the men began and the INS was alerted, but the two men were already in the United States and could not be found. Since the FBI was not aware of a specific threat, the FAA and other authorities were not notified, sources said.

One FAA official suggests they should have been. "Quite often, we knew of a threat somewhere out in the world, somewhere out in the field. Either the agency had it or the Bureau had it but the FAA did not," said Kenneth Quinn, former FAA general counsel.

Partly to blame for such a communication failure, sources say, is a longstanding culture that discourages sharing information for fear of compromising sources. Attorney General John Ashcroft has proposed the establishment of joint terrorist task forces to try to fix the problem.